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Geng W, Fang Y, Bao C, Pan Z, Yue Y. Emission of five OAM dispersive waves in dispersion-engineered double-ring core fiber. Sci Rep 2024; 14:8474. [PMID: 38605163 PMCID: PMC11009397 DOI: 10.1038/s41598-024-57587-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024] Open
Abstract
Beams carrying orbital angular momentum (OAM) have exhibited significant potential across various fields, such as metrology, image coding, and optical communications. High-performance broadband coherent OAM sources are critical to the operation of optical systems. The emission of dispersive waves facilitates the efficient transfer of energy to distant spectral domains while preserving the coherence among the generated frequency components. Light sources that maintain consistency over a wide range can increase the efficiency of optical communication systems and improve the measurement accuracy in imaging and metrology. In this work, we propose a germanium-doped double ring-core fiber for five OAM dispersive waves (DWs) generation. The OAM1,1 mode supported in the fiber exhibits three zero-dispersion wavelengths (ZDWs) located at 1275, 1720 and 2325 nm. When pumped under normal dispersion, the output spectrum undergoes broadening and exhibits five DWs, situated around 955, 1120, 1450, 2795 and 2965 nm, respectively. Concomitant with blue-shifted and red-shifted dispersive waves, the spectrum spans from 895 to 3050 nm with high coherence. The effect of the fiber and input pulse parameters on DWs generation, as well as the underlying dynamics of the dispersive wave generation process, are discussed. As expected, the number and location of DWs generated in the output spectrum have agreement with the prediction of the phase-matching condition. Overall, this multiple DWs generation method in the proposed fiber paves the way for developing efficient and coherent OAM light sources in fiber-based optical systems.
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Affiliation(s)
- Wenpu Geng
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Yuxi Fang
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Changjing Bao
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Zhongqi Pan
- Department of Electrical & Computer Engineering, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA
| | - Yang Yue
- School of Information and Communications Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
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2
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Ren K, Guo Y, Zhai Y, Zhang L. On-chip octave-spanning flat supercontinuum in all-normal-dispersion silicon nitride waveguides. OPTICS EXPRESS 2024; 32:8527-8536. [PMID: 38571110 DOI: 10.1364/oe.509430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/23/2024] [Indexed: 04/05/2024]
Abstract
On-chip supercontinuum generators have emerged as an attractive optical source with small size, broad spectrum and high power efficiency. Nevertheless, there has long been a trade-off between spectral uniformity and bandwidth. We propose a novel silicon nitride waveguide with flat saddle-shaped all-normal dispersion, particularly for enhancing the nonlinear interactions over a wide band. By launching a 250-fs 30-kW input pulse, an ultra-flat (-6 dB) octave-spanning supercontinuum extending from 638 nm to 1477 nm can be generated. We analyze the performance of the supercontinuum generator in terms of spectral flatness and bandwidth under different input pulse conditions. Thanks to mature dispersion engineering, the pump wavelength can be flexibly selected within the flat dispersion region. The generated supercontinuum, therefore, can be applied to different spectral regions by shifting the center wavelength.
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3
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Eilkaer Hansen R, Meldgaard Moltke A, Bang O. High-power supercontinuum lasers with a flat blue spectrum through pump modulation: a numerical study. OPTICS LETTERS 2023; 48:1574-1577. [PMID: 37221713 DOI: 10.1364/ol.485130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/23/2023] [Indexed: 05/25/2023]
Abstract
We numerically investigate high-power, modulational instability-based supercontinuum sources. Such sources have spectra that reach the infrared material absorption edge and as a result the spectrum has a strong narrow blue peak (dispersive wave group velocity matched to solitons at the infrared loss edge) followed by a significant dip in the neighboring longer-wavelength region. In a wide range of applications one prefers a broader and more flat blue part within a certain minimum and maximum power spectral density. From the perspective of fiber degradation it would be desirable to achieve this at reduced pump peak powers. We show that it is possible to improve the flatness by more than a factor of 3 by modulating the input peak power, although this comes at the expense of slightly higher relative intensity noise. Specifically, we consider a standard 6.6 W, 80 MHz supercontinuum source with a 455 nm blue edge, which uses 7 ps pump pulses. We then modulate its peak power to generate a pump pulse train having two and three different sub-pulses.
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4
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Zhou J, Kang R, Cheng P, Liu Z, Zhao J, Zuo Z. Simulation on a dispersion-managed 4H-SiC on insulator waveguide for infrared supercontinuum generation. APPLIED OPTICS 2023; 62:34-38. [PMID: 36606846 DOI: 10.1364/ao.476706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
We demonstrate infrared supercontinuum generation in 4H-SiC on insulator slab waveguides. The effect of waveguide geometry parameters on dispersion is investigated to switch the zero-dispersion wavelength close to the pump wavelength. The 1 cm long 4H-SiC waveguide is pumped by 100 fs pulses at 1550 nm with 2000 W peak power, and the generated supercontinuum extends from ∼1000 to ∼3560n m (at 20 dB level). This work shows that 4H-SiC has significant potential as on-chip photonic sources for spectroscopic applications in infrared wavelengths.
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5
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Supercontinuum generation in a nonlinear ultra-silicon-rich nitride waveguide. Sci Rep 2022; 12:9487. [PMID: 35676414 PMCID: PMC9177728 DOI: 10.1038/s41598-022-13734-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/09/2022] [Indexed: 12/05/2022] Open
Abstract
Supercontinuum generation is demonstrated in a 3-mm-long ultra-silicon-rich nitride (USRN) waveguide by launching 500 fs pulses centered at 1555 nm with a pulse energy of 17 pJ. The generated supercontinuum is experimentally characterized to possess a high spectral coherence, with an average |g12| exceeding 0.90 across the wavelength range of the coherence measurement (1260 nm to 1700 nm). Numerical simulations further indicate a high coherence over the full spectrum. The experimentally measured supercontinuum agrees well with the theoretical simulations based on the generalized nonlinear Schrödinger equation. The generated broadband spectra using 500 fs pulses possessing high spectral coherence provide a promising route for CMOS-compatible light sources for self-referencing applications, metrology, and imaging.
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6
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Nishizawa N, Kitajima S, Sakakibara Y. Spectral peaking in an ultrashort-pulse fiber laser oscillator with a molecular gas cell. OPTICS LETTERS 2022; 47:2422-2425. [PMID: 35561370 DOI: 10.1364/ol.458643] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/10/2022] [Indexed: 06/15/2023]
Abstract
Here we report the demonstration of a spectral peaking phenomenon in a fiber laser oscillator. An HCN gas cell was inserted in an ultrashort-pulse Er-doped fiber laser with single-wall carbon nanotubes. Sech2-shaped ultrashort pulses with intense multiple sharp spectral peaks were stably generated. When the generated pulses were coupled into highly nonlinear fiber, enhanced multiple spectral peaks were generated by periodical spectral peaking in the optical fiber. The characteristics and physical mechanism of spectral peaking in the fiber laser were investigated via numerical simulations. As the magnitude of absorption was increased, the magnitude of the generated spectral peaks increased almost exponentially. It was clarified that the spectral peaks were generated through the accumulation of filtering components generated in each round trip.
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7
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Bernstein L, Ramier A, Wu J, Aiello VD, Béland MJ, Lin CP, Yun SH. Ultrahigh resolution spectral-domain optical coherence tomography using the 1000-1600 nm spectral band. BIOMEDICAL OPTICS EXPRESS 2022; 13:1939-1947. [PMID: 35519264 PMCID: PMC9045918 DOI: 10.1364/boe.443654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 01/10/2023]
Abstract
Ultrahigh resolution optical coherence tomography (UHR-OCT) can image microscopic features that are not visible with the standard OCT resolution of 5-15 µm. In previous studies, high-speed UHR-OCT has been accomplished within the visible (VIS) and near-infrared (NIR-I) spectral ranges, specifically within 550-950 nm. Here, we present a spectral domain UHR-OCT system operating in a short-wavelength infrared (SWIR) range from 1000 to 1600 nm using a supercontinuum light source and an InGaAs-based spectrometer. We obtained an axial resolution of 2.6 µm in air, the highest ever recorded in the SWIR window to our knowledge, with deeper penetration into tissues than VIS or NIR-I light. We demonstrate imaging of conduction fibers of the left bundle branch in freshly excised porcine hearts. These results suggest a potential for deep-penetration, ultrahigh resolution OCT in intraoperative applications.
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Affiliation(s)
- Liane Bernstein
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02140, USA,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Antoine Ramier
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02140, USA,Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jiamin Wu
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02140, USA,Department of Automation, Tsinghua University, Beijing 100084, China,Institute for Brain and Cognitive Science, Tsinghua University, Beijing 100084, China
| | - Vera D. Aiello
- Laboratory of Pathology, Heart Institute, University of São Paulo Medical School, São Paulo, Brazil
| | - Marie J. Béland
- Division of Pediatric Cardiology, The Montreal Children’s Hospital of the McGill University Health Centre, Montréal, Quebec, Canada
| | - Charles P. Lin
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02140, USA,Department of Dermatology, Harvard Medical School, Boston, MA, USA
| | - Seok-Hyun Yun
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02140, USA,Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA,Department of Dermatology, Harvard Medical School, Boston, MA, USA,
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8
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Ji X, Mojahed D, Okawachi Y, Gaeta AL, Hendon CP, Lipson M. Millimeter-scale chip-based supercontinuum generation for optical coherence tomography. SCIENCE ADVANCES 2021; 7:eabg8869. [PMID: 34533990 PMCID: PMC8448444 DOI: 10.1126/sciadv.abg8869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Supercontinuum sources for optical coherence tomography (OCT) have raised great interest as they provide broad bandwidth to enable high resolution and high power to improve imaging sensitivity. Commercial fiber-based supercontinuum systems require high pump powers to generate broad bandwidth and customized optical filters to shape/attenuate the spectra. They also have limited sensitivity and depth performance. We introduce a supercontinuum platform based on a 1-mm2 Si3N4 photonic chip for OCT. We directly pump and efficiently generate supercontinuum near 1300 nm without any postfiltering. With a 25-pJ pump pulse, we generate a broadband spectrum with a flat 3-dB bandwidth of 105 nm. Integrating the chip into a spectral domain OCT system, we achieve 105-dB sensitivity and 1.81-mm 6-dB sensitivity roll-off with 300-μW optical power on sample. We image breast tissue to demonstrate strong imaging performance. Our chip will pave the way toward portable OCT and incorporating integrated photonics into optical imaging technologies.
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Affiliation(s)
- Xingchen Ji
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Diana Mojahed
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Yoshitomo Okawachi
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Alexander L. Gaeta
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Corresponding author. (M.L.); (C.P.H.)
| | - Michal Lipson
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Corresponding author. (M.L.); (C.P.H.)
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9
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Non-Destructive Subsurface Inspection of Marine and Protective Coatings Using Near- and Mid-Infrared Optical Coherence Tomography. COATINGS 2021. [DOI: 10.3390/coatings11080877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Near- and mid-infrared optical coherence tomography (OCT) is evaluated as a non-destructive and non-contact reflection imaging modality for inspection of industrial and marine coatings. Near-infrared OCT was used to obtain high-resolution images (~6/2 µm lateral/axial) of hidden subsurface cracks and defects in a resin base coating, which had been exposed to high pressure and high temperature to study coating degradation in hostile environments. Mid-infrared OCT was employed for high-resolution (~15/8.5 µm lateral/axial) subsurface inspection of highly scattering marine coatings, demonstrating monitoring of wet film thickness and particle dispersion during curing of a 210 µm layer of antifouling coating, and detection of substrate corrosion through 369 µm of high-gloss alkyd enamel. Combining high-resolution and fast, non-invasive scanning, OCT is therefore considered a promising tool for studying coating performance and for industrial inspection.
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10
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Papež N, Dallaev R, Kaspar P, Sobola D, Škarvada P, Ţălu Ş, Ramazanov S, Nebojsa A. Characterization of GaAs Solar Cells under Supercontinuum Long-Time Illumination. MATERIALS 2021; 14:ma14020461. [PMID: 33477904 PMCID: PMC7833441 DOI: 10.3390/ma14020461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023]
Abstract
This work is dedicated to the description of the degradation of GaAs solar cells under continuous laser irradiation. Constant and strong exposure of the solar cell was performed over two months. Time-dependent electrical characteristics are presented. The structure of the solar cells was studied at the first and last stages of degradation test. The data from Raman spectroscopy, reflectometry, and secondary ion mass spectrometry confirm displacement of titanium and aluminum atoms. X-ray photoelectron spectroscopy showed a slight redistribution of oxygen bonds in the anti-corrosion coating.
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Affiliation(s)
- Nikola Papež
- Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic; (N.P.); (R.D.); (P.K.); (D.S.); (P.Š.)
| | - Rashid Dallaev
- Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic; (N.P.); (R.D.); (P.K.); (D.S.); (P.Š.)
| | - Pavel Kaspar
- Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic; (N.P.); (R.D.); (P.K.); (D.S.); (P.Š.)
| | - Dinara Sobola
- Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic; (N.P.); (R.D.); (P.K.); (D.S.); (P.Š.)
- CEITEC BUT – Brno University of Technology, Purkyňova 656/123, 61200 Brno, Czech Republic;
- Department of Inorganic Chemistry and Chemical Ecology, Dagestan State University, Makhachkala, St. M. Gadjieva 43-a, 367015 Dagestan Republic, Russia;
| | - Pavel Škarvada
- Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic; (N.P.); (R.D.); (P.K.); (D.S.); (P.Š.)
- CEITEC BUT – Brno University of Technology, Purkyňova 656/123, 61200 Brno, Czech Republic;
| | - Ştefan Ţălu
- Directorate of Research, Development and Innovation Management (DMCDI), Technical University of Cluj-Napoca, Constantin Daicoviciu Street, no. 15, Cluj-Napoca, 400020 Cluj County, Romania
- Correspondence: or ; Tel.: +40-264-401-200; Fax: +40-264-592-055
| | - Shikhgasan Ramazanov
- Department of Inorganic Chemistry and Chemical Ecology, Dagestan State University, Makhachkala, St. M. Gadjieva 43-a, 367015 Dagestan Republic, Russia;
| | - Alois Nebojsa
- CEITEC BUT – Brno University of Technology, Purkyňova 656/123, 61200 Brno, Czech Republic;
- Department of Solid State Physics and Surfaces, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 61600 Brno, Czech Republic
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11
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Qin J, An L. Optical Coherence Tomography for Ophthalmology Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 3233:197-216. [PMID: 34053029 DOI: 10.1007/978-981-15-7627-0_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Optical coherence tomography (OCT) is a depth-resolved imaging modality, which is able to achieve micrometer-scale resolution within biological tissue noninvasively. In the past 30 years, researchers all around the world had made several essential efforts on techniques relevant to OCT. OCT has become a routine process for eye diseases with different types. In this chapter, the three important stages in the development of OCT are briefly illustrated, including the time domain OCT (TD-OCT), the frequency domain OCT (FD-OCT) and the optical coherence tomography angiography (OCTA). Each of the technique has made great progress for use on living human eye imaging in clinical applications. TD-OCT was first proposed and commercialized, which is able to achieve acceptable 2D depth-resolved cross-sectional images of human retina in vivo. FD-OCT was the upgraded OCT technique compared with TD-OCT. By capturing the coherent signal within the Fourier space, the FD-OCT could improve the image sensitivity compared with TD-OCT, and achieve dozens of kilo hertz imaging speed. OCTA is the newest developments of OCT technique, which is able to visualize the micro vasculature networks of human retina in vivo. With OCTA technique, the newest ophthalmologic OCT system is able to achieve detailed diagnosis for both micro-structure and vasculature abnormalities for clinical applications. The further development of OCT technique on imaging speed, contrast, resolution, field of view, and so on will make OCT to be a more powerful tool for clinical usages.
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Affiliation(s)
- Jia Qin
- Innovation and Entrepreneurship Teams Project of Guangdong Pearl River Talents Program, Guangdong Weiren Meditech Co., Ltd, Foshan, Guangdong, People's Republic of China
| | - Lin An
- Innovation and Entrepreneurship Teams Project of Guangdong Pearl River Talents Program, Guangdong Weiren Meditech Co., Ltd, Foshan, Guangdong, People's Republic of China
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12
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Ling Y, Wang M, Yao X, Gan Y, Schmetterer L, Zhou C, Su Y. Effect of spectral leakage on the image formation of Fourier-domain optical coherence tomography. OPTICS LETTERS 2020; 45:6394-6397. [PMID: 33258820 DOI: 10.1364/ol.404654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
We report on the investigation of spectral leakage's impact on the reconstruction of Fourier-domain optical coherence tomography (FD-OCT). We discuss the shift-variant nature introduced by the spectral leakage and develop a novel spatial-domain FD-OCT image formation model. A proof-of-concept phantom experiment is conducted to validate our model. Compared with previous models, the proposed framework could better describe the image formation process, especially when the fineness of the axial structure approaches the theoretical resolution limit.
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13
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Huang C, Zhu J, Aruna Gandhi MS, Li Q. Effects of two weak continuous-wave triggers on picosecond pulse pumped supercontinuum generation. APPLIED OPTICS 2020; 59:8560-8567. [PMID: 33104534 DOI: 10.1364/ao.400792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
The promising advancement of supercontinuum generation in optical fibers has initiated significant interest in recent research studies and several continuing applications. We numerically corroborate the effects of picosecond pulse pumped supercontinuum (SC) by using two weak continuous-wave (CW) triggers with 1% pump intensity. Compared with SC with one CW trigger, adding two CW triggers (1% pump power), both near the modulation instability peaks, can achieve wider spectra for a picosecond pulse pumped SC. Furthermore, good coherence properties may be achieved in the wavelength range from 1300-2000 nm when one CW trigger is near the pump center wavelength and the other CW trigger is distant from the pump. In our simulations, putting two CW triggers on the same side (concerning the pump wavelength) or putting them on different sides have similar effects on SC spectral and temporal coherence properties. Therefore, by engineering the wavelengths of two CW triggers to offer better bandwidth or coherence, we envision that the proposed technique could play a significant role in the generation of SC.
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14
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Heng J, Liu P, Zhang Z. Spectral broadening in chirped-pulse optical parametric oscillators based on KTiOAsO 4. OPTICS LETTERS 2020; 45:5085-5088. [PMID: 32932459 DOI: 10.1364/ol.404580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
We report a chirped-pulse optical parametric oscillator (CPOPO) based on a KTiOAsO4 (KTA) crystal. Due to the relatively low ratio between its second-order and third-order nonlinear susceptibility, a single KTA crystal could provide parametric gain and intra-cavity spectral broadening simultaneously in a CPOPO. Numerical simulations show that a signal-bandwidth of 390 nm can be obtained from a KTA-based CPOPO, and the pulses can be de-chirped with a width of ∼20fs outside the OPO cavity. Experimentally, from a fiber-laser-pumped OPO with a 3-mm-long KTA crystal, we obtained a signal wave covering 1332-1667 nm, with a -20dB bandwidth of 45.3 THz, around 12 times as much as the gain-bandwidth of the KTA crystal.
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15
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Lu J, Liu X, Bruch AW, Zhang L, Wang J, Yan J, Tang HX. Ultraviolet to mid-infrared supercontinuum generation in single-crystalline aluminum nitride waveguides. OPTICS LETTERS 2020; 45:4499-4502. [PMID: 32796993 DOI: 10.1364/ol.398257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate ultrabroadband supercontinuum generation from ultraviolet to mid-infrared wavelengths in single-crystalline aluminum nitride waveguides. Tunable dispersive waves are observed at the mid-infrared regime by precisely controlling the waveguide widths. In addition, ultraviolet light is generated through cascaded second-harmonic generation in the modal phase-matched waveguides. Numerical simulation indicates a high degree of coherence of the generated spectrum at around the telecom pump and two dispersive waves. Our results establish a reliable path for multiple octave supercontinuum comb generation in single-crystalline aluminum nitride to enable applications including precision frequency metrology and spectroscopy.
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16
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Cheong H, Devalla SK, Pham TH, Zhang L, Tun TA, Wang X, Perera S, Schmetterer L, Aung T, Boote C, Thiery A, Girard MJA. DeshadowGAN: A Deep Learning Approach to Remove Shadows from Optical Coherence Tomography Images. Transl Vis Sci Technol 2020; 9:23. [PMID: 32818084 PMCID: PMC7396186 DOI: 10.1167/tvst.9.2.23] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/13/2019] [Indexed: 12/05/2022] Open
Abstract
Purpose To remove blood vessel shadows from optical coherence tomography (OCT) images of the optic nerve head (ONH). Methods Volume scans consisting of 97 horizontal B-scans were acquired through the center of the ONH using a commercial OCT device for both eyes of 13 subjects. A custom generative adversarial network (named DeshadowGAN) was designed and trained with 2328 B-scans in order to remove blood vessel shadows in unseen B-scans. Image quality was assessed qualitatively (for artifacts) and quantitatively using the intralayer contrast—a measure of shadow visibility ranging from 0 (shadow-free) to 1 (strong shadow). This was computed in the retinal nerve fiber layer (RNFL), the inner plexiform layer (IPL), the photoreceptor (PR) layer, and the retinal pigment epithelium (RPE) layer. The performance of DeshadowGAN was also compared with that of compensation, the standard for shadow removal. Results DeshadowGAN decreased the intralayer contrast in all tissue layers. On average, the intralayer contrast decreased by 33.7 ± 6.81%, 28.8 ± 10.4%, 35.9 ± 13.0%, and 43.0 ± 19.5% for the RNFL, IPL, PR layer, and RPE layer, respectively, indicating successful shadow removal across all depths. Output images were also free from artifacts commonly observed with compensation. Conclusions DeshadowGAN significantly corrected blood vessel shadows in OCT images of the ONH. Our algorithm may be considered as a preprocessing step to improve the performance of a wide range of algorithms including those currently being used for OCT segmentation, denoising, and classification. Translational Relevance DeshadowGAN could be integrated to existing OCT devices to improve the diagnosis and prognosis of ocular pathologies.
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Affiliation(s)
- Haris Cheong
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Sripad Krishna Devalla
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Tan Hung Pham
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Liang Zhang
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Tin Aung Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Xiaofei Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Shamira Perera
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Ophthalmology Department. Duke-NUS Medical School, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Ophthalmology Department. Duke-NUS Medical School, Singapore
| | - Tin Aung
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Craig Boote
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,School of Optometry & Vision Sciences, Cardiff University, UK.,Newcastle Research & Innovation Institute, Singapore
| | - Alexandre Thiery
- Department of Statistics and Applied Probability, National University of Singapore, Singapore
| | - Michaël J A Girard
- Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
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Huang X, Pan Z, Hu A, Dong J. High-power, ultra-broadband supercontinuum light generated in a single-mode fiber pumped with a nanosecond passively Q-switched microchip laser. APPLIED OPTICS 2020; 59:3019-3025. [PMID: 32400578 DOI: 10.1364/ao.385296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/23/2020] [Indexed: 06/11/2023]
Abstract
The compact, high-power, broadband continuum sources are extremely needed for developing portable instruments for various applications such as optical coherence tomography, high-resolution spectroscopy, and so on. Here, we develop a compact high-power, ultra-broadband supercontinuum (SC) light source in a single-mode fiber (SMF) pumped with a Yb:YAG/Cr4+:YAG passively Q-switched microchip laser oscillating at 1030 nm. The spectral bandwidth of the SC light is over 1150 nm covering from 600 to 1750 nm. The maximum average output power is 181.8 mW at an input pump power of 880 mW. The optical efficiency is 20.6%, and the net conversion efficiency is as high as 51.6% with respect to the pump power coupled into the fiber. The ultra-broadband spectrum of the SC generated in the SMF is caused by the intermodal four-wave mixing (IMFWM) and cascade stimulated Raman scattering effects. Various transverse modes have been experimentally observed in SC beam generated in the SMF. Wavelength-dependent transverse modes propagating in the SMF participating in the IMFWM process dramatically expand the spectral range in the visible region. The experimental results are basically consistent with the theoretical simulations of broadband SC generated in the SMF through the IMFWM process.
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Pinkert MA, Simmons ZJ, Niemeier RC, Dai B, Woods LB, Hall TJ, Campagnola PJ, Rogers JD, Eliceiri KW. Platform for quantitative multiscale imaging of tissue composition. BIOMEDICAL OPTICS EXPRESS 2020; 11:1927-1946. [PMID: 32341858 PMCID: PMC7173879 DOI: 10.1364/boe.383248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 05/14/2023]
Abstract
Changes in the multi-level physical structure of biological features going from cellular to tissue level composition is a key factor in many major diseases. However, we are only beginning to understand the role of these structural changes because there are few dedicated multiscale imaging platforms with sensitivity at both the cellular and macrostructural spatial scale. A single platform reduces bias and complications from multiple sample preparation methods and can ease image registration. In order to address these needs, we have developed a multiscale imaging system using a range of imaging modalities sensitive to tissue composition: Ultrasound, Second Harmonic Generation Microscopy, Multiphoton Microscopy, Optical Coherence Tomography, and Enhanced Backscattering. This paper details the system design, the calibration for each modality, and a demonstration experiment imaging a rabbit eye.
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Affiliation(s)
- Michael A Pinkert
- Morgridge Institute for Research, 330 N Orchard St, Madison, WI 53715, USA
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Medical Physics, 1111 Highland Ave, Madison, WI 53705, USA
| | - Zachary J Simmons
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Ryan C Niemeier
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Bing Dai
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
| | - Lauren B Woods
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Timothy J Hall
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Medical Physics, 1111 Highland Ave, Madison, WI 53705, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Paul J Campagnola
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Medical Physics, 1111 Highland Ave, Madison, WI 53705, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Jeremy D Rogers
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Medical Physics, 1111 Highland Ave, Madison, WI 53705, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Kevin W Eliceiri
- Morgridge Institute for Research, 330 N Orchard St, Madison, WI 53715, USA
- University of Wisconsin Madison, Laboratory for Optical and Computational Instrumentation, 1675 Observatory Drive, Madison, WI 53706, USA
- University of Wisconsin Madison, Department of Medical Physics, 1111 Highland Ave, Madison, WI 53705, USA
- University of Wisconsin Madison, Department of Biomedical Engineering, 1550 Engineering Dr, Madison, WI 53706, USA
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Li Z, Yuan J, Mei C, Li F, Zhou X, Yan B, Wu Q, Wang K, Sang X, Long K, Yu C. Multi-octave mid-infrared supercontinuum and frequency comb generation in a suspended As 2Se 3 ridge waveguide. APPLIED OPTICS 2019; 58:8404-8410. [PMID: 31873322 DOI: 10.1364/ao.58.008404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
In this paper, we numerically investigate the mid-infrared supercontinuum (SC) generation in a suspended ${{\rm As}_2}{{\rm Se}_3}$As2Se3 ridge waveguide, which is designed with the two zero-dispersion wavelengths. Simulation results show that when the pump pulses at wavelength 3.3 µm with width of 100 fs and peak power of 900 W are launched into the anomalous dispersion region of the designed waveguide with a length of 0.87 mm, the SC can be generated in the wavelength range from 1.76 to 14.42 µm (more than three octaves), extending deep into the "fingerprint" region. The stability of the generated SC is confirmed by the first-order coherence. Moreover, we demonstrate the performance of the SC-based frequency comb by assuming a 50 pulse pump source at a repetition rate of 100 MHz.
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20
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Tao Y, Chen SP, Xu H. Hundred-watt level linearly polarized visible supercontinuum generation. OPTICS EXPRESS 2019; 27:26044-26049. [PMID: 31510464 DOI: 10.1364/oe.27.026044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/03/2019] [Indexed: 06/10/2023]
Abstract
An all-fiber linearly polarized supercontinuum (SC) laser source with 93 W average output power and spectrum ranging from 520 nm to 2300 nm is experimentally demonstrated. The linearly-polarized SC is generated in a piece of 2.6 m long polarization-maintaining photonic crystal fiber (PM-PCF), pumped by a polarization-maintaining picosecond Yb-doped master oscillator power amplifier (PM-MOPA). The source exhibits a flat spectrum from 600 nm to 1880 nm at -10 dB level except for the residual pump peak. A new method is proposed to measure the polarization extinction ratio (PER) of each single wavelength of the broadband supercontinuum at a high-power level, resulting in larger than 16 dB PER from 900 nm to 1600 nm and larger than 15 dB PER from 540 nm to 650 nm. To our knowledge, this is the first demonstration of hundred-watt level linearly polarized visible SC and the first demonstration of PER measurement of each single wavelength within such a wide spectrum range.
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21
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Tarnowski K, Martynkien T, Mergo P, Sotor J, Soboń G. Compact all-fiber source of coherent linearly polarized octave-spanning supercontinuum based on normal dispersion silica fiber. Sci Rep 2019; 9:12313. [PMID: 31444393 PMCID: PMC6707307 DOI: 10.1038/s41598-019-48726-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/12/2019] [Indexed: 11/30/2022] Open
Abstract
We report the generation of coherent octave-spanning supercontinuum in an all-fiber system, without any free-space optical components. The setup uses the femtosecond fiber laser as a pump and an all-normal dispersion microstructured fiber as a medium for supercontinuum generation. The generated spectrum is characterized both experimentally and numerically and shows a broad bandwidth (1.1−2.2 μm), a high signal to noise ratio reaching 100 at maximum, a high coherence (closing to 1), linear polarization and average output power up to 57 mW. The source is characterized by exceptional simplicity and does not require any alignment (the nonlinear fiber is spliced to the pump) which finally opens the path to outside-lab applications of supercontinuum radiation.
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Affiliation(s)
- Karol Tarnowski
- Department of Optics and Photonics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Tadeusz Martynkien
- Department of Optics and Photonics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Paweł Mergo
- Laboratory of Optical Fiber Technology, Maria Curie-Sklodowska University, pl. M. Curie-Sklodowskiej 3, 20-031, Lublin, Poland
| | - Jarosław Sotor
- Laser & Fiber Electronics Group, Faculty of Electronics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Grzegorz Soboń
- Laser & Fiber Electronics Group, Faculty of Electronics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
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22
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O'Connor SP, Marble CB, Nodurft DT, Noojin GD, Boretsky AR, Wharmby AW, Scully MO, Yakovlev VV. Filamentation in Atmospheric Air with Tunable 1100-2400 nm Near-Infrared Femtosecond Laser Source. Sci Rep 2019; 9:12049. [PMID: 31427739 PMCID: PMC6700063 DOI: 10.1038/s41598-019-48542-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/29/2019] [Indexed: 11/09/2022] Open
Abstract
Intense femtosecond pulse filamentation in open-air has been utilized for long distance optical communication and remote sensing, but it results in nonlinear-effect driven eye hazards which are not addressed by current eye safety standards. A systematic study of filamentation in atmospheric air was performed using a tunable 100 fs near-infrared laser (1100 nm-2400 nm). While undergoing filamentation, each source wavelength was spectrally broadened resulting in supercontinuum and third harmonic generation in the visible and near-IR spectrum. We record the spectra at the center and fringes of the supercontinuum as it is imaged onto a planar surface. In a full beam collection regime, we report the energy of the sub-1000 nm light generation for source wavelengths from 1100 nm to 1600 nm and compare the energy density to the maximum permissible exposure values under the ANSI Z136.1 laser safety standard.
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Affiliation(s)
- Sean P O'Connor
- Texas A&M University, College Station, TX, 77843, USA. .,Engility Corporation, 4241 Woodcock Dr. Ste. B-100, San Antonio, TX, 78228, USA.
| | - Christopher B Marble
- Texas A&M University, College Station, TX, 77843, USA.,Consortium Research Fellows Program, 4214 King Street, First Floor Alexandria, Virginia, 22302, USA
| | - Dawson T Nodurft
- Texas A&M University, College Station, TX, 77843, USA. .,Engility Corporation, 4241 Woodcock Dr. Ste. B-100, San Antonio, TX, 78228, USA.
| | - Gary D Noojin
- Engility Corporation, 4241 Woodcock Dr. Ste. B-100, San Antonio, TX, 78228, USA
| | - Adam R Boretsky
- Engility Corporation, 4241 Woodcock Dr. Ste. B-100, San Antonio, TX, 78228, USA
| | - Andrew W Wharmby
- 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Optical Radiation Branch, 4141 Petroleum Rd., JBSA Fort Sam Houston, San Antonio, TX, 78234, USA
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Zhao S, Yang H, Huang Y, Xiao Y. Generation of tunable ultra-short pulse sequences in a quasi-discrete spectral supercontinuum by dark solitons. OPTICS EXPRESS 2019; 27:23539-23548. [PMID: 31510629 DOI: 10.1364/oe.27.023539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
We explore how to acquire the tunable ultra-short pulse sequences in a quasi-discrete spectral supercontinuum (SC) via the formation of dark solitons in a fiber with two zero dispersion wavelengths (ZDWs). These dark solitons are produced by pumping two pulses in the normal dispersion that are identical but delayed one with respect to the other. Few-cycle pulses with high power as dual pumps experience temporal breakdown, resulting in a nearly-complete conversion of pump energy into two normal dispersion regions to form the ultra-short pulse sequences separated by dark solitons. The spectral interference of these generated ultra-short pulses gives rise to the isolated narrow-band sources, shaping a quasi-discrete spectral SC. Based on the combined effect of group-velocity dispersion and the initial time delay between dual pumps, the spectral width of narrow-band sources behaves in such a similar manner to the temporal width of ultra-short pulses that they are different in two normal dispersion regions. Moreover, they can be regulated considerably by tuning the time delay and pump power. Furthermore, the control of time delay and pump power can bolster the manipulation on the number of ultra-short pulses and narrow-band sources.
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24
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Aghayari E, Jamshidi Ghaleh K. High-power supercontinuum generation by noise-like pulse amplification in Yb-doped fiber amplifier operating in a nonlinear regime. APPLIED OPTICS 2019; 58:4020-4024. [PMID: 31158152 DOI: 10.1364/ao.58.004020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
In this paper, we report on a supercontinuum generation by amplifying noise-like pulses (NLPs) in a nonlinear Yb-doped fiber amplifier. The NLP source is a homemade Yb-doped all-fiber ring oscillator based on nonlinear polarization rotation mode-locking method. NLPs possess a repetition rate of 11.57 MHz, energy of 16.5 nJ, and 3 dB spectral bandwidth of 42 nm. The intensity autocorrelation function of NLPs has a broad pedestal and a narrow central spike. The pedestal and the spike have temporal widths of 63 ps and 92 fs, respectively. The NLPs are amplified by a Yb-doped fiber nonlinear power amplifier to achieve output power of 7.5 W. Nonlinear effects in the amplifier drastically broaden the spectrum of NLPs and generate high-power supercontinuum light with 10 dB spectral bandwidth of 1130 nm (from 1037 to 2167 nm). The presented supercontinuum generation system is an all-fiber compact structure and has the advantage of not requiring long single-mode, nonlinear, or photonic crystal fibers.
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25
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Tankam P, He Z, Thuret G, Hindman HB, Canavesi C, Escudero JC, Lépine T, Gain P, Rolland JP. Capabilities of Gabor-domain optical coherence microscopy for the assessment of corneal disease. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-17. [PMID: 31020822 PMCID: PMC6479593 DOI: 10.1117/1.jbo.24.4.046002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/21/2019] [Indexed: 05/03/2023]
Abstract
To identify the microstructural modification of the corneal layers during the course of the disease, optical technologies have been pushing the boundary of innovation to achieve cellular resolution of deep layers of the cornea. Gabor-domain optical coherence microscopy (GD-OCM), an optical coherence tomography-based technique that can achieve an isotropic of ∼2-μm resolution over a volume of 1 mm × 1 mm × 1.2 mm, was developed to investigate the microstructural modifications of corneal layers in four common corneal diseases. Since individual layer visualization without cutting through several layers is challenging due to corneal curvature, a flattening algorithm was developed to remove the global curvature of the endothelial layer and display the full view of the endothelium and Descemet's membrane in single en face images. As a result, GD-OCM revealed the qualitative changes in size and reflectivity of keratocytes in Fuchs endothelial corneal dystrophy (FECD), which varied by the degree of disease. More importantly, elongated shape and hyperactivation characteristics of keratocytes, associated with the early development of guttae, appeared to start in the posterior stroma very early in the disease process and move toward the anterior stroma during disease progression. This work opens a venue into the pathogenesis of FECD.
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Affiliation(s)
- Patrice Tankam
- Indiana University, School of Optometry, Bloomington, Indiana, United States
- Address all correspondence to Patrice Tankam, E-mail:
| | - Zhiguo He
- Jean Monnet University, Laboratory Biology, Engineering and Imaging of Corneal Graft, Faculty of Medicine, Saint-Etienne, France
| | - Gilles Thuret
- Jean Monnet University, Laboratory Biology, Engineering and Imaging of Corneal Graft, Faculty of Medicine, Saint-Etienne, France
- Institut Universitaire de France, Paris, France
| | | | | | - Johana Coyoc Escudero
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Thierry Lépine
- Université de Lyon, Centre National de la Recherche Scientifique, Laboratoire Hubert Curien, Saint-Etienne, France
| | - Philippe Gain
- Jean Monnet University, Laboratory Biology, Engineering and Imaging of Corneal Graft, Faculty of Medicine, Saint-Etienne, France
| | - Jannick P. Rolland
- LighTopTech Corp., West Henrietta, New York, United States
- University of Rochester, The Institute of Optics, Rochester, New York, United States
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26
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Lu J, Surya JB, Liu X, Xu Y, Tang HX. Octave-spanning supercontinuum generation in nanoscale lithium niobate waveguides. OPTICS LETTERS 2019; 44:1492-1495. [PMID: 30874684 DOI: 10.1364/ol.44.001492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/24/2019] [Indexed: 05/27/2023]
Abstract
We demonstrate octave-spanning supercontinuum generation in unpoled lithium niobate waveguides, which are engineered to possess anomalous dispersion and pumped by a turn-key femtosecond laser centered at 1560 nm. Tunable dispersive waves and strong phase-matched second-harmonic generation are both observed by controlling the widths of the waveguides. The major features of the experimental spectra are reproduced by numerical modeling of the generalized nonlinear Schrödinger equation, which can be used to guide waveguide designs for tailoring the supercontinuum spectrum. Our results identify a path to a simple and integrable supercontinuum source in lithium niobate nanophotonic platform and will enable new capabilities in precision frequency metrology.
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27
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Xu F, Yuan J, Mei C, Yan B, Zhou X, Wu Q, Wang K, Sang X, Yu C, Farrell G. Highly coherent supercontinuum generation in a polarization-maintaining CS 2-core photonic crystal fiber. APPLIED OPTICS 2019; 58:1386-1392. [PMID: 30874022 DOI: 10.1364/ao.58.001386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
In this paper, we design a polarization-maintaining CS2-core photonic crystal fiber (PM-CCPCF). The two air holes in the x direction are infiltrated with C2H5OH in order to introduce birefringence. By optimizing the structure parameters of the PM-CCPCF, it is demonstrated that the x-polarization fundamental mode has an all-normal dispersion profile and the corresponding y-polarization fundamental mode has an anomalous dispersion profile for a pump wavelength of 1.76 μm. Then, we investigate the supercontinuum (SC) generations when different fiber lengths, pump peak powers, and pump pulse widths are chosen, respectively. Simulation results show that for the x-polarization and y-polarization fundamental modes, highly coherent SCs can be generated by appropriately choosing the fiber length and pump pulse parameters. Finally, nonlinear propagation dynamics are analysed when the optimized fiber length and pump pulse parameters are used. The bandwidth of the SCs generated for the x-polarization and y-polarization fundamental modes can be up to 0.82 and 1.26 octave, respectively.
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Jia H, Yang R, Tian J, Zhang W. High-power pulse, pulse pair, and pulse train generated by breathers in dispersion exponentially decreasing fiber. APPLIED OPTICS 2019; 58:912-919. [PMID: 30874135 DOI: 10.1364/ao.58.000912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
Based on the derived rational solutions of the nonautonomous nonlinear Schrödinger equation with varying coefficients, we present a simple scheme to generate a high-power pulse, pulse pair, and pulse train with non-oscillating amplitudes in dispersion exponentially decreasing fiber. Without requiring elimination of the background, the stable pulse train can be generated from the first-order Akhmediev breather, and the high-power pulse and pulse pair can be generated from the second-order Kuznetsov-Ma breather. Moreover, it is found that the characteristics of these pulses can be controlled by adjusting the eigenvalue parameter and fiber parameters. The results presented here are expected to be useful in large-capacity and high-power optical communication systems.
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29
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Mikkonen T, Amiot C, Aalto A, Patokoski K, Genty G, Toivonen J. Broadband cantilever-enhanced photoacoustic spectroscopy in the mid-IR using a supercontinuum. OPTICS LETTERS 2018; 43:5094-5097. [PMID: 30320828 DOI: 10.1364/ol.43.005094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/10/2018] [Indexed: 06/08/2023]
Abstract
We demonstrate cantilever-enhanced photoacoustic spectroscopy in the mid-infrared using a supercontinuum source. The approach is broadband and allows for higher photoacoustic signal intensity and an enhanced signal-to-noise ratio as compared to systems employing conventional black body radiation sources. Using this technique, we perform spectroscopic measurements of the full ro-vibrational band structure of water vapor at 1900 nm and methane at 3300 nm with relative signal enhancement factors of 70 and 19, respectively, when compared to measurements that use the black body radiation source. Our results offer a novel perspective for photoacoustic detection opening the door to sensitive broadband analyzers in the mid-infrared spectral region.
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30
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Marble CB, Clary JE, Noojin GD, O'Connor SP, Nodurft DT, Wharmby AW, Rockwell BA, Scully MO, Yakovlev VV. Z-scan measurements of water from 1150 to 1400 nm. OPTICS LETTERS 2018; 43:4196-4199. [PMID: 30160750 DOI: 10.1364/ol.43.004196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
Understanding the nonlinear properties of water is essential for laser surgery applications, as well as understanding supercontinuum generation in water. Unfortunately, the nonlinear properties of water for wavelengths longer than 1064 nm are poorly understood. We extend the application of the Z-scan technique in water to determine its nonlinear refractive index (n2) and nonlinear absorption (β) for wavelengths in the 1150-1400 nm range, where linear absorption is also significant. We observe the wavelength-dependent variation of the nonlinear properties of water around the water absorption band.
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31
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A Review of Mid-Infrared Supercontinuum Generation in Chalcogenide Glass Fibers. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8050707] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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32
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Chen L, Gao W, Chen L, Wang P, Ni C, Chen X, Zhou Y, Zhang W, Hu J, Liao M, Suzuki T, Ohishi Y. Numerical study on supercontinuum generation by different optical modes in AsSe 2-As 2S 5 chalcogenide microstructured fiber. APPLIED OPTICS 2018; 57:382-390. [PMID: 29400785 DOI: 10.1364/ao.57.000382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
We investigate supercontinuum generation (SCG) in AsSe2-As2S5 chalcogenide microstructured optical fibers (MOFs) pumped by different optical modes. The influence on SCG by different optical modes including the fundamental and high-order modes is analyzed numerically. The evolution of the supercontinuum (SC) is investigated by changing the pump wavelength (2120, 2580, and 3280 nm) and peak power (from 200 to 1000 W) of each optical mode (LP01,LP11,LP31) in the MOFs with different fiber lengths. SCG in MOFs with different core diameters is also simulated. The different optical modes cause the variation of the chromatic dispersion profile and the effective nonlinearity, which induces different mechanisms of the SCG and changes the spectral range. The maximum SC spectral range covers 12.931 μm from 1.389 to 14.320 μm when pumped by the LP11 mode with the peak power of 1000 W at 3280 nm. The simulated results will be instructive for the experimental SCG up to the midinfrared waveband longer than 10 μm.
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33
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Singh N, Xin M, Vermeulen D, Shtyrkova K, Li N, Callahan PT, Magden ES, Ruocco A, Fahrenkopf N, Baiocco C, Kuo BPP, Radic S, Ippen E, Kärtner FX, Watts MR. Octave-spanning coherent supercontinuum generation in silicon on insulator from 1.06 μm to beyond 2.4 μm. LIGHT, SCIENCE & APPLICATIONS 2018; 7:17131. [PMID: 30839639 PMCID: PMC6107049 DOI: 10.1038/lsa.2017.131] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 05/19/2023]
Abstract
Efficient complementary metal-oxide semiconductor-based nonlinear optical devices in the near-infrared are in strong demand. Due to two-photon absorption in silicon, however, much nonlinear research is shifting towards unconventional photonics platforms. In this work, we demonstrate the generation of an octave-spanning coherent supercontinuum in a silicon waveguide covering the spectral region from the near- to shortwave-infrared. With input pulses of 18 pJ in energy, the generated signal spans the wavelength range from the edge of the silicon transmission window, approximately 1.06 to beyond 2.4 μm, with a -20 dB bandwidth covering 1.124-2.4 μm. An octave-spanning supercontinuum was also observed at the energy levels as low as 4 pJ (-35 dB bandwidth). We also measured the coherence over an octave, obtaining , in good agreement with the simulations. In addition, we demonstrate optimization of the third-order dispersion of the waveguide to strengthen the dispersive wave and discuss the advantage of having a soliton at the long wavelength edge of an octave-spanning signal for nonlinear applications. This research paves the way for applications, such as chip-scale precision spectroscopy, optical coherence tomography, optical frequency metrology, frequency synthesis and wide-band wavelength division multiplexing in the telecom window.
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Affiliation(s)
- Neetesh Singh
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ming Xin
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Diedrik Vermeulen
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Katia Shtyrkova
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nanxi Li
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- John A. Paulson School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138, USA
| | - Patrick T Callahan
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Emir Salih Magden
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alfonso Ruocco
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nicholas Fahrenkopf
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Christopher Baiocco
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Bill P-P Kuo
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92039, USA
| | - Stojan Radic
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92039, USA
| | - Erich Ippen
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Franz X Kärtner
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Centre for Free Electron Laser Science (CFEL)-DESY and University of Hamburg, Hamburg 22607, Germany
| | - Michael R Watts
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Wu CL, Huang JY, Ou DH, Liao TW, Chiu YJ, Shih MH, Lin YY, Chu AK, Lee CK. Efficient wavelength conversion with low operation power in a Ta 2O 5-based micro-ring resonator. OPTICS LETTERS 2017; 42:4804-4807. [PMID: 29216115 DOI: 10.1364/ol.42.004804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/12/2017] [Indexed: 06/07/2023]
Abstract
The Ta2O5-based micro-ring resonator with an unloaded quality factor of 182,000 has been demonstrated to realize efficient nonlinear wavelength generation. The propagation loss of the resonator is 0.5 cm-1, and the buildup factor of the ring resonator is estimated to be ∼50. With a high buildup factor of the ring structure, the four-wave-mixing (FWM) conversion efficiency of -30 dB is achieved in the resonator with a pump power of 6 mW. Based on power-dependent FWM results, the nonlinear refractive index of Ta2O5 is estimated to be 1.4×10-14 cm2/W at a wavelength of ∼1550 nm. The demonstration of an enhanced FWM process in the Ta2O5-based micro-ring cavity implies the possibility of realizing FWM-based optical parametric oscillation in a Ta2O5-based micro-ring resonator.
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Kawagoe H, Yamanaka M, Nishizawa N. Axial resolution and signal-to-noise ratio in deep-tissue imaging with 1.7-μm high-resolution optical coherence tomography with an ultrabroadband laser source. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:85002. [PMID: 28777837 DOI: 10.1117/1.jbo.22.8.085002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
We investigated the axial resolution and signal-to-noise ratio (SNR) characteristics in deep-tissue imaging by 1.7-μm optical coherence tomography (OCT) with the axial resolution of 4.3 μm in tissue. Because 1.7-μm OCT requires a light source with a spectral width of more than 300 nm full-width at half maximum to achieve such high resolution, the axial resolution in the tissue might be degraded by spectral distortion and chromatic dispersion mismatching between the sample and reference arms. In addition, degradation of the axial resolution would also lead to reduced SNR. Here, we quantitatively evaluated the degradation of the axial resolution and the resulting decrease in SNR by measuring interference signals through a lipid mixture serving as a turbid tissue phantom with large scattering and absorption coefficients. Although the axial resolution was reduced by a factor of ∼6 after passing through a 2-mm-thick tissue phantom, our result clearly showed that compensation of the dispersion mismatching allowed us to achieve an axial resolution of 4.3 μm in tissue and improve the SNR by ∼5 dB compared with the case where dispersion mismatching was not compensated. This improvement was also confirmed in the observation of a hamster’s cheek pouch in a buffer solution.
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Affiliation(s)
- Hiroyuki Kawagoe
- , Department of Quantum Engineering, Furo-cho, Chikusa-ku, Nagoya, Aichi
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36
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Porquez JG, Cole RA, Tabarangao JT, Slepkov AD. Brighter CARS hypermicroscopy via "spectral surfing" of a Stokes supercontinuum. OPTICS LETTERS 2017; 42:2255-2258. [PMID: 28614325 DOI: 10.1364/ol.42.002255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
We present a simple technique that significantly enhances the interaction of pump pulses with a supercontinuum Stokes generated by a particular nonlinear fiber for time-gated experiments such as coherent anti-Stokes Raman scattering (CARS). The enhancement is achieved through a synchronized power-tuning/time delay scheme that we call spectral surfing. In this Letter, we introduce spectral surfing and demonstrate how its application to an economical CARS hypermicroscopy scheme increases the brightness, contrast, and spectral scanning range, while potentially reducing sample light exposure.
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37
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Gao W, Wu X. Differences between time domain and Fourier domain optical coherence tomography in imaging tissues. J Microsc 2017; 268:119-128. [PMID: 28600827 DOI: 10.1111/jmi.12592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 12/21/2022]
Abstract
It has been numerously demonstrated that both time domain and Fourier domain optical coherence tomography (OCT) can generate high-resolution depth-resolved images of living tissues and cells. In this work, we compare the common points and differences between two methods when the continuous and random properties of live tissue are taken into account. It is found that when relationships that exist between the scattered light and tissue structures are taken into account, spectral interference measurements in Fourier domain OCT (FDOCT) is more advantageous than interference fringe envelope measurements in time domain OCT (TDOCT) in the cases where continuous property of tissue is taken into account. It is also demonstrated that when random property of tissue is taken into account FDOCT measures the Fourier transform of the spatial correlation function of the refractive index and speckle phenomena will limit the effective limiting imaging resolution in both TDOCT and FDOCT. Finally, the effective limiting resolution of both TDOCT and FDOCT are given which can be used to estimate the effective limiting resolution in various practical applications.
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Affiliation(s)
- W Gao
- Department of Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, P. R. China
| | - X Wu
- Department of Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, P. R. China
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38
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Hontinfinde R, Coulibaly S, Megret P, Taki M, Wuilpart M. Nondestructive distributed measurement of supercontinuum generation along highly nonlinear optical fibers. OPTICS LETTERS 2017; 42:1716-1719. [PMID: 28454143 DOI: 10.1364/ol.42.001716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Supercontinuum generation (SCG) in optical fibers arises from the spectral broadening of an intense light, which results from the interplay of both linear and nonlinear optical effects. In this Letter, a nondestructive optical time domain reflectometry method is proposed for the first time, to the best of our knowledge, to measure the spatial (longitudinal) evolution of the SC induced along an optical fiber. The method was experimentally tested on highly nonlinear fibers. The experimental results are in a good agreement with the optical spectra measured at the fiber outputs.
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Diouf M, Salem AB, Cherif R, Saghaei H, Wague A. Super-flat coherent supercontinuum source in As 38.8Se 61.2 chalcogenide photonic crystal fiber with all-normal dispersion engineering at a very low input energy. APPLIED OPTICS 2017; 56:163-169. [PMID: 28085846 DOI: 10.1364/ao.56.000163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We numerically report super-flat coherent mid-infrared supercontinuum (MIR-SC) generation in a chalcogenide As38.8Se61.2 photonic crystal fiber (PCF). The dispersion and nonlinear parameters of As38.8Se61.2 chalcogenide PCFs by varying the diameter of the air holes are engineered to obtain all-normal dispersion (ANDi) with high nonlinearities. We show that launching low-energy 50 fs optical pulses with 0.88 kW peak power (corresponding to pulse energy of 0.05 nJ) at a central wavelength of 3.7 μm into a 5 cm long ANDi-PCF generates a flat-top coherent MIR-SC spanning from 2900 to 4575 nm with a high spectral flatness of 3 dB. This ultra-wide and flattened spectrum has excellent stability and coherence properties that can be used for MIR applications such as medical diagnosis of diseases, atmospheric pollution monitoring, and drug detection.
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Saad A, Cho Y, Ahmed F, Jun MBG. Numerical Approach to Modeling and Characterization of Refractive Index Changes for a Long-Period Fiber Grating Fabricated by Femtosecond Laser. MATERIALS (BASEL, SWITZERLAND) 2016; 9:ma9110941. [PMID: 28774060 PMCID: PMC5457259 DOI: 10.3390/ma9110941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/24/2016] [Accepted: 11/02/2016] [Indexed: 06/07/2023]
Abstract
A 3D finite element model constructed to predict the intensity-dependent refractive index profile induced by femtosecond laser radiation is presented. A fiber core irradiated by a pulsed laser is modeled as a cylinder subject to predefined boundary conditions using COMSOL5.2 Multiphysics commercial package. The numerically obtained refractive index change is used to numerically design and experimentally fabricate long-period fiber grating (LPFG) in pure silica core single-mode fiber employing identical laser conditions. To reduce the high computational requirements, the beam envelope method approach is utilized in the aforementioned numerical models. The number of periods, grating length, and grating period considered in this work are numerically quantified. The numerically obtained spectral growth of the modeled LPFG seems to be consistent with the transmission of the experimentally fabricated LPFG single mode fiber. The sensing capabilities of the modeled LPFG are tested by varying the refractive index of the surrounding medium. The numerically obtained spectrum corresponding to the varied refractive index shows good agreement with the experimental findings.
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Affiliation(s)
- Akram Saad
- Department of Mechanical Engineering, University of Victoria, Victoria, BC V8W 2Y2, Canada.
| | - Yonghyun Cho
- Department of Mechanical Engineering, University of Victoria, Victoria, BC V8W 2Y2, Canada.
| | - Farid Ahmed
- Department of Mechanical Engineering, University of Victoria, Victoria, BC V8W 2Y2, Canada.
| | - Martin Byung-Guk Jun
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47906, USA.
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Gao W, Xu Q, Li X, Zhang W, Hu J, Li Y, Chen X, Yuan Z, Liao M, Cheng T, Xue X, Suzuki T, Ohishi Y. Experimental investigation on supercontinuum generation by single, dual, and triple wavelength pumping in a silica photonic crystal fiber. APPLIED OPTICS 2016; 55:9514-9520. [PMID: 27869854 DOI: 10.1364/ao.55.009514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the supercontinuum (SC) generation in an 1 cm long silica photonic crystal fiber (PCF) pumped by the pulse sources with single, dual, and triple wavelengths, respectively. The silica PCF has two zero-dispersion wavelengths at 900 and 2620 nm, respectively. When pumped by a single wavelength, the SC spectral range covers about 1000 nm. When pumped by dual and triple wavelengths, the SC spectral range covers wider than 2000 nm. Both the SC spectral range and the flatness are improved obviously when pumped by triple wavelengths. The maximum SC spectral range is obtained when the silica PCF is pumped by the triple wavelengths at 800, 1450, and 1785 nm. The SC spectral range covers 2810 nm from 350 to 3160 nm wider than three octaves. The 10 dB bandwidth covers 2280 nm from 450 to 2730 nm wider than two octaves. This is the first investigation on comparison of the SCs generated by different pump wavelengths up to three experimentally. The generated SC spectra have covered the full transmission window of silica fiber.
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42
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Lin JH, Chen CL, Chan CW, Chang WC, Chen YH. Investigation of noise-like pulses from a net normal Yb-doped fiber laser based on a nonlinear polarization rotation mechanism. OPTICS LETTERS 2016; 41:5310-5313. [PMID: 27842120 DOI: 10.1364/ol.41.005310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigated the characteristics of noise-like pulses (NLPs) from a net normal dispersion Yb-doped fiber laser (YDFL) by using the grating pairs (GPs) inside the laser cavity as a dispersion compensation element. Without the insertion of the slit inside the laser cavity, the operation of the YDFL is at an NLP state with the double-scale intensity autocorrelation trace once the mode-locked pulses are generated. Through the dispersion delay line outside the laser cavity, the substantial temporal compression of the NLPs has been demonstrated. After inserting the slit between the GPs as a bandpass filter, the operation state of the YDFL can be switched between the NLPs and the dissipated solitons by means of a pump power. Besides, the NLPs can also transit to the bound solitons as the YDFL is operated within long and short wavelength regimes through the spatial shift of the slit.
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Visible to near-infrared supercontinuum generation in yttrium orthosilicate bulk crystal and ion implanted planar waveguide. Sci Rep 2016; 6:31612. [PMID: 27527662 PMCID: PMC4985816 DOI: 10.1038/srep31612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 07/25/2016] [Indexed: 12/16/2022] Open
Abstract
This paper reports on the supercontinuum generation in yttrium orthosilicate bulk crystal and 6-mm-long ion implanted planar waveguide. The waveguide is fabricated by 6 MeV oxygen ions implantation with fluence of 5 × 1014 ions/cm2 at room temperature. The yttrium orthosilicate bulk crystal and waveguide are pumped using a mode-locked Ti:Sapphire laser with a center wavelength of 800 nm. The generated broadest supercontinuum spans 720 nm (at −30 dB points) from 380 to 1100 nm in bulk crystal and 510 nm (at −30 dB points) from 490 to 1000 nm in ion implanted waveguide, respectively. Compared to the bulk crystal, the ion implanted waveguide requires almost three orders of magnitude lower pump power to achieve a similar level of broadening. The supercontinuum is generated in the normal dispersion regime and exhibits a relatively smooth spectral shape. Our research findings indicate that ion implantation is an efficient method to produce waveguide in yttrium orthosilicate crystal for low-threshold supercontinuum generation.
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Ravichandran NK, Wijesinghe RE, Shirazi MF, Park K, Jeon M, Jung W, Kim J. Depth enhancement in spectral domain optical coherence tomography using bidirectional imaging modality with a single spectrometer. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:76005. [PMID: 27401937 DOI: 10.1117/1.jbo.21.7.076005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/16/2016] [Indexed: 06/06/2023]
Abstract
A method for depth enhancement is presented using a bidirectional imaging modality for spectral domain optical coherence tomography (SD-OCT). Two precisely aligned sample arms along with two reference arms were utilized in the optical configuration to scan the samples. Using exemplary images of the optical resolution target, Scotch tape, a silicon sheet with two needles, and a leaf, we demonstrated how the developed bidirectional SD-OCT imaging method increases the ability to characterize depth-enhanced images. The results of the developed system were validated by comparing the images with the standard OCT configuration (single-sample arm setup). Given the advantages of higher resolution and the ability to visualize deep morphological structures, this method can be utilized to increase the depth dependent fall-off in samples with limited thickness. Thus, the proposed bidirectional imaging modality is apt for cross-sectional imaging of entire samples, which has the potential capability to improve the diagnostic ability.
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Affiliation(s)
- Naresh Kumar Ravichandran
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Ruchire Eranga Wijesinghe
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Muhammad Faizan Shirazi
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Kibeom Park
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Mansik Jeon
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Woonggyu Jung
- Ulsan National Institute of Science and Technology, Department of Biomedical Engineering, 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Jeehyun Kim
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
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45
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Luo J, Sun B, Liu J, Yan Z, Li N, Tan EL, Wang Q, Yu X. Mid-IR supercontinuum pumped by femtosecond pulses from thulium doped all-fiber amplifier. OPTICS EXPRESS 2016; 24:13939-13945. [PMID: 27410556 DOI: 10.1364/oe.24.013939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a mid-infrared (mid-IR) supercontinuum (SC) light source pumped by femtosecond pulses from a thulium doped fiber amplifier (TDFA) at 2 μm. An octave-spanning spectrum from 1.1 to 3.7 μm with an average power of 253 mW has been obtained from a single mode ZBLAN fiber. Spectral flatness of 10 dB over a 1390 nm range has been obtained in the mid-IR region from 1940 - 3330 nm. It is resulted from the enhanced self phase modulation process in femtosecond regime. The all-fiber configuration makes such broadband coherent source a compact candidate for various applications.
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46
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Närhi M, Turunen J, Friberg AT, Genty G. Experimental Measurement of the Second-Order Coherence of Supercontinuum. PHYSICAL REVIEW LETTERS 2016; 116:243901. [PMID: 27367389 DOI: 10.1103/physrevlett.116.243901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Indexed: 06/06/2023]
Abstract
We measure experimentally the second-order coherence properties of supercontinuum generated in a photonic crystal fiber. Our approach is based on measuring separately the quasicoherent and quasistationary contributions to the cross-spectral density and mutual coherence functions using a combination of interferometric and nonlinear gating techniques. This allows us to introduce two-dimensional coherence spectrograms which provide a direct characterization and convenient visualization of the spectrotemporal coherence properties. The measured second-order coherence functions are in very good agreement with numerical simulations based on the generalized nonlinear Schrödinger equation. Our results pave the way towards the full experimental characterization of supercontinuum coherence properties. More generally, they provide a generic approach for the complete experimental measurement of the coherence of broadband sources.
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Affiliation(s)
- Mikko Närhi
- Department of Physics, Tampere University of Technology, P.O. Box 527, FI-33101 Tampere, Finland
| | - Jari Turunen
- Institute of Photonics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Ari T Friberg
- Institute of Photonics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Goëry Genty
- Department of Physics, Tampere University of Technology, P.O. Box 527, FI-33101 Tampere, Finland
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47
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Liu X, Pu M, Zhou B, Krückel CJ, Fülöp A, Torres-Company V, Bache M. Octave-spanning supercontinuum generation in a silicon-rich nitride waveguide. OPTICS LETTERS 2016; 41:2719-2722. [PMID: 27304272 DOI: 10.1364/ol.41.002719] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We experimentally show octave-spanning supercontinuum generation in a nonstoichiometric silicon-rich nitride waveguide when pumped by femtosecond pulses from an erbium fiber laser. The pulse energy and bandwidth are comparable to results achieved in stoichiometric silicon nitride waveguides, but our material platform is simpler to manufacture. We also observe wave-breaking supercontinuum generation by using orthogonal pumping in the same waveguide. Additional analysis reveals that the waveguide height is a powerful tuning parameter for generating mid-infrared dispersive waves while keeping the pump in the telecom band.
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48
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Choi JW, Chen GFR, Ng DKT, Ooi KJA, Tan DTH. Wideband nonlinear spectral broadening in ultra-short ultra - silicon rich nitride waveguides. Sci Rep 2016; 6:27120. [PMID: 27272558 PMCID: PMC4897639 DOI: 10.1038/srep27120] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/16/2016] [Indexed: 11/28/2022] Open
Abstract
CMOS-compatible nonlinear optics platforms with high Kerr nonlinearity facilitate the generation of broadband spectra based on self-phase modulation. Our ultra - silicon rich nitride (USRN) platform is designed to have a large nonlinear refractive index and low nonlinear losses at 1.55 μm for the facilitation of wideband spectral broadening. We investigate the ultrafast spectral characteristics of USRN waveguides with 1-mm-length, which have high nonlinear parameters (γ ∼ 550 W(-1)/m) and anomalous dispersion at 1.55 μm wavelength of input light. USRN add-drop ring resonators broaden output spectra by a factor of 2 compared with the bandwidth of input fs laser with the highest quality factors of 11000 and 15000. Two - fold self phase modulation induced spectral broadening is observed using waveguides only 430 μm in length, whereas a quadrupling of the output bandwidth is observed with USRN waveguides with a 1-mm-length. A broadening factor of around 3 per 1 mm length is achieved in the USRN waveguides, a value which is comparatively larger than many other CMOS-compatible platforms.
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Affiliation(s)
- Ju Won Choi
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Rd. 487372, Singapore
| | - George F. R. Chen
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Rd. 487372, Singapore
| | - D. K. T. Ng
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way #08-01 Innovis, 138634, Singapore
| | - Kelvin J. A. Ooi
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Rd. 487372, Singapore
| | - Dawn T. H. Tan
- Photonics Devices and System Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Rd. 487372, Singapore
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Yuan W, Mavadia-Shukla J, Xi J, Liang W, Yu X, Yu S, Li X. Optimal operational conditions for supercontinuum-based ultrahigh-resolution endoscopic OCT imaging. OPTICS LETTERS 2016; 41:250-3. [PMID: 26766686 PMCID: PMC5881115 DOI: 10.1364/ol.41.000250] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We investigated the optimal operational conditions for utilizing a broadband supercontinuum (SC) source in a portable 800 nm spectral-domain (SD) endoscopic OCT system to enable high resolution, high-sensitivity, and high-speed imaging in vivo. A SC source with a 3-dB bandwidth of ∼246 nm was employed to obtain an axial resolution of ∼2.7 μm (in air) and an optimal detection sensitivity of ∼-107 dB with an imaging speed up to 35 frames/s (at 70 k A-scans/s). The performance of the SC-based SD-OCT endoscopy system was demonstrated by imaging guinea pig esophagus in vivo, achieving image quality comparable to that acquired with a broadband home-built Ti:sapphire laser.
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Affiliation(s)
- Wu Yuan
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Jessica Mavadia-Shukla
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Jiefeng Xi
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Wenxuan Liang
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Xiaoyun Yu
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Shaoyong Yu
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Xingde Li
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
- Corresponding author:
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50
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Zhang B, Jin A, Ma P, Chen S, Hou J. High-power near-infrared linearly-polarized supercontinuum generation in a polarization-maintaining Yb-doped fiber amplifier. OPTICS EXPRESS 2015; 23:28683-28690. [PMID: 26561136 DOI: 10.1364/oe.23.028683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report an all-fiber linearly-polarized (LP) supercontinuum (SC) source with high average power generated in a polarization-maintaining (PM) master-oscillation power-amplifier (MOPA). The experimental configuration comprises an LP picosecond pulsed laser and three PM Yd-doped fiber amplifiers (YDFA). The output has the average power of 124.8 W with the spectrum covering from 850 to 1900 nm. The measured polarization extinction ratio (PER) of the whole SC source is about 85% which verifies the SC an LP source. This work is, to our best knowledge, the highest output average power of an LP SC source that ever reported. The influence of PM fiber splicing method on the LP SC property is investigated by splicing the PM fibers with slow axis parallel or perpendicularly aligned, and also an LP SC with low output power is demonstrated.
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