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Lapointe J, Grégoire A, Bérubé JP, Vallée R. Enhancing Evanescent Wave Coupling of Near-Surface Waveguides with Plasmonic Nanoparticles. SENSORS (BASEL, SWITZERLAND) 2023; 23:3945. [PMID: 37112288 PMCID: PMC10144640 DOI: 10.3390/s23083945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/01/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
Evanescent field excitation is a powerful means to achieve a high surface-to-bulk signal ratio for bioimaging and sensing applications. However, standard evanescent wave techniques such as TIRF and SNOM require complex microscopy setups. Additionally, the precise positioning of the source relative to the analytes of interest is required, as the evanescent wave is critically distance-dependent. In this work, we present a detailed investigation of evanescent field excitation of near-surface waveguides written using femtosecond laser in glass. We studied the waveguide-to-surface distance and refractive index change to attain a high coupling efficiency between evanescent waves and organic fluorophores. First, our study demonstrated a reduction in sensing efficiency for waveguides written at their minimum distance to the surface without ablation as the refractive index contrast of the waveguide increased. While this result was anticipated, it had not been previously demonstrated in the literature. Moreover, we found that fluorescence excitation by waveguides can be enhanced using plasmonic silver nanoparticles. The nanoparticles were also organized in linear assemblies, perpendicular to the waveguide, with a wrinkled PDMS stamp technique, which resulted in an excitation enhancement of over 20 times compared to the setup without nanoparticles.
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Affiliation(s)
- Jerome Lapointe
- Centre d’Optique, Photonique et Laser, Université Laval, 2375 Rue de la Terrasse, Québec, QC G1V 0A6, Canada; (A.G.); (R.V.)
| | - Alexandre Grégoire
- Centre d’Optique, Photonique et Laser, Université Laval, 2375 Rue de la Terrasse, Québec, QC G1V 0A6, Canada; (A.G.); (R.V.)
- Département de Chimie, Université Laval, 2375 Rue de la Terrasse, Québec, QC G1V 0A6, Canada
| | - Jean-Philippe Bérubé
- Ciena Corporation, 505 Boulevard du Parc Technologique, Suite 100, Québec, QC G1P 4S9, Canada;
| | - Réal Vallée
- Centre d’Optique, Photonique et Laser, Université Laval, 2375 Rue de la Terrasse, Québec, QC G1V 0A6, Canada; (A.G.); (R.V.)
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2
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Bogris A, Burger NA, Makris KG, Loppinet B, Fytas G. Intermixed Time-Dependent Self-Focusing and Defocusing Nonlinearities in Polymer Solutions. ACS PHOTONICS 2022; 9:722-728. [PMID: 35211646 PMCID: PMC8855434 DOI: 10.1021/acsphotonics.1c01917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Low-power visible light can lead to spectacular nonlinear effects in soft-matter systems. The propagation of visible light through transparent solutions of certain polymers can experience either self-focusing or defocusing nonlinearity, depending on the solvent. We show how the self-focusing and defocusing responses can be captured by a nonlinear propagation model using local spatial and time-integrating responses. We realize a remarkable pattern formation in ternary solutions and model it assuming a linear combination of the self-focusing and defocusing nonlinearities in the constituent solvents. This versatile response of solutions to light irradiation may introduce a new approach for self-written waveguides and patterns.
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Affiliation(s)
- Athanasios Bogris
- FORTH,
Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
- Department
of Materials Science and Technology, University
of Crete, 70013 Heraklion, Crete, Greece
| | - Nikolaos A. Burger
- FORTH,
Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
- Department
of Materials Science and Technology, University
of Crete, 70013 Heraklion, Crete, Greece
| | - Konstantinos G. Makris
- FORTH,
Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
- Department
of Physics, University of Crete, Heraklion 71003, Greece
| | - Benoit Loppinet
- FORTH,
Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
| | - George Fytas
- FORTH,
Institute of Electronic Structure and Laser, 70013 Heraklion, Crete, Greece
- Max-Planck
Institute for Polymer Research, 55128 Mainz, Germany
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3
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Picazo-Bueno JA, Micó V. Optical module for single-shot quantitative phase imaging based on the transport of intensity equation with field of view multiplexing. OPTICS EXPRESS 2021; 29:39904-39919. [PMID: 34809345 DOI: 10.1364/oe.439047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
We present a cost-effective, simple, and robust method that enables single-shot quantitative phase imaging (QPI) based on the transport of intensity equation (TIE) using an add-on optical module that can be assembled into the exit port of any regular microscope. The module integrates a beamsplitter (BS) cube (placed in a non-conventional way) for duplicating the output image onto the digital sensor (field of view - FOV - multiplexing), a Stokes lens (SL) for astigmatism compensation (introduced by the BS cube), and an optical quality glass plate over one of the FOV halves for defocusing generation (needed for single-shot TIE algorithm). Altogether, the system provides two laterally separated intensity images that are simultaneously recorded and slightly defocused one to each other, thus enabling accurate QPI by conventional TIE-based algorithms in a single snapshot. The proposed optical module is first calibrated for defining the configuration providing best QPI performance and, second, experimentally validated by using different phase samples (static and dynamic ones). The proposed configuration might be integrated in a compact three-dimensional (3D) printed module and coupled to any conventional microscope for QPI of dynamic transparent samples.
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4
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Violakis G, Bogris A, Pispas S, Fytas G, Loppinet B, Pissadakis S. Optically formed rubbery waveguide interconnects. OPTICS LETTERS 2021; 46:5437-5440. [PMID: 34724495 DOI: 10.1364/ol.435052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
Light induced self-written waveguides (LISWs) with unique elongation characteristics and low optical loss are formed in a monodispersed polyisoprene solution using a low-power laser photopolymerization process, while their light transmission characteristics are exemplified in the flexible interconnection of two single-mode optical fibers operating in the visible/near infrared wavelengths. The LISWs formed exhibit rubbery properties, allowing extensibilities upon cases from 400% to 800%, while still retaining significant optical transmission. The rubber elasticity enables sustaining LISWs at stressed lengths longer than 500 µm propagation losses from 1.0 to 2.9 dB/mm.
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5
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Cruz JL, Barmenkov YO, Díez A, Andres MV. Measurement of phase and group refractive indices and dispersion of thermo-optic and strain-optic coeffients of optical fibers using weak fiber Bragg gratings. APPLIED OPTICS 2021; 60:2824-2832. [PMID: 33798158 DOI: 10.1364/ao.418049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
In this work we report on the measurement, with record accuracy, of the absolute modal effective refraction index (phase index) of single-mode optical fibers by using Bragg gratings. We also demonstrate a new method to measure the group index of the fibers from the grating's Bragg wavelength. We present as well the characterization of the thermo-optic and strain-optic coefficients as a function of the wavelength; the values we have obtained are the closest to those of pristine fiber measured with gratings technology so far. The phase index is measured with a set of gratings in the wavelength ranges from 1509 to 1563 nm, and the group index is obtained from the wavelength dependence of the phase index. Very weak gratings with reflectivity down to 10-3 have been used in order to minimize the perturbation of the pristine fiber. Results are presented at a temperature of 22°C and zero strain after preliminary calibration of the thermo-optic and strain-optic coefficients as a function of the wavelength. Accuracies better than 3×10-5 and 7×10-4 have been achieved for the phase and group indices, respectively. It is also shown that the main source of error relates to the uncertainty in pitch of the phase masks used for grating inscription. The technique is useful for testing different kinds of fibers including telecommunication, amplifying, and polarization maintaining.
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6
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Lapointe J, Bérubé JP, Ledemi Y, Dupont A, Fortin V, Messaddeq Y, Vallée R. Nonlinear increase, invisibility, and sign inversion of a localized fs-laser-induced refractive index change in crystals and glasses. LIGHT, SCIENCE & APPLICATIONS 2020; 9:64. [PMID: 32351688 PMCID: PMC7171118 DOI: 10.1038/s41377-020-0298-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/20/2020] [Accepted: 03/19/2020] [Indexed: 05/14/2023]
Abstract
Multiphoton absorption via ultrafast laser focusing is the only technology that allows a three-dimensional structural modification of transparent materials. However, the magnitude of the refractive index change is rather limited, preventing the technology from being a tool of choice for the manufacture of compact photonic integrated circuits. We propose to address this issue by employing a femtosecond-laser-induced electronic band-gap shift (FLIBGS), which has an exponential impact on the refractive index change for propagating wavelengths approaching the material electronic resonance, as predicted by the Kramers-Kronig relations. Supported by theoretical calculations, based on a modified Sellmeier equation, the Tauc law, and waveguide bend loss calculations, we experimentally show that several applications could take advantage of this phenomenon. First, we demonstrate waveguide bends down to a submillimeter radius, which is of great interest for higher-density integration of fs-laser-written quantum and photonic circuits. We also demonstrate that the refractive index contrast can be switched from negative to positive, allowing direct waveguide inscription in crystals. Finally, the effect of the FLIBGS can compensate for the fs-laser-induced negative refractive index change, resulting in a zero refractive index change at specific wavelengths, paving the way for new invisibility applications.
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Affiliation(s)
- Jerome Lapointe
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Jean-Philippe Bérubé
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Yannick Ledemi
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Albert Dupont
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Vincent Fortin
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Younes Messaddeq
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
| | - Réal Vallée
- Centre d’Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, G1V 0A6 Québec, QC Canada
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7
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Dardikman-Yoffe G, Roitshtain D, Mirsky SK, Turko NA, Habaza M, Shaked NT. PhUn-Net: ready-to-use neural network for unwrapping quantitative phase images of biological cells. BIOMEDICAL OPTICS EXPRESS 2020; 11:1107-1121. [PMID: 32206402 PMCID: PMC7041455 DOI: 10.1364/boe.379533] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/19/2019] [Accepted: 01/07/2020] [Indexed: 05/17/2023]
Abstract
We present a deep-learning approach for solving the problem of 2π phase ambiguities in two-dimensional quantitative phase maps of biological cells, using a multi-layer encoder-decoder residual convolutional neural network. We test the trained network, PhUn-Net, on various types of biological cells, captured with various interferometric setups, as well as on simulated phantoms. These tests demonstrate the robustness and generality of the network, even for cells of different morphologies or different illumination conditions than PhUn-Net has been trained on. In this paper, for the first time, we make the trained network publicly available in a global format, such that it can be easily deployed on every platform, to yield fast and robust phase unwrapping, not requiring prior knowledge or complex implementation. By this, we expect our phase unwrapping approach to be widely used, substituting conventional and more time-consuming phase unwrapping algorithms.
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Affiliation(s)
- Gili Dardikman-Yoffe
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Darina Roitshtain
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Simcha K. Mirsky
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nir A. Turko
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Mor Habaza
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Natan T. Shaked
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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8
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Drouin A, Lorre P, Boisvert JS, Loranger S, Iezzi VL, Kashyap R. Spatially resolved cross-sectional refractive index profile of fs laser-written waveguides using a genetic algorithm. OPTICS EXPRESS 2019; 27:2488-2498. [PMID: 30732286 DOI: 10.1364/oe.27.002488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
Laser-written waveguides in glass have many potential applications as photonic devices. However, there is little knowledge of the actual profile of the usually asymmetric refractive index (RI) change across the femtosecond (fs) laser-written waveguides. We show, here, a new nondestructive method to measure any symmetric or asymmetric two-dimensional RI profile of fs laser-written waveguides in transparent materials. The method is also suitable for the measurement of the RI profile of any other type of waveguide. A Mach-Zehnder interferometer is used to obtain the phase shift of light propagating transversely through the RI-modified region. A genetic algorithm is then used to determine the matching cross-sectional RI profile based on the known waveguide shape and dimensions. A validation of the method with the comparison to a RNF measurement of the industry-standard SMF-28 is presented, as well as a demonstration of its versatility with measurements on fs laser-written waveguides.
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9
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Lages E, Cardoso W, Almeida GFB, Siman L, Mesquita O, Mendonça CR, Agero U, Pádua S. Measurement of the refractive index profile of waveguides using defocusing microscopy. APPLIED OPTICS 2018; 57:8699-8704. [PMID: 30461946 DOI: 10.1364/ao.57.008699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/13/2018] [Indexed: 06/09/2023]
Abstract
Defocusing microscopy (DM) is a bright-field optical microscopy technique often used to obtain structural parameters of objects with low difference in refractive index in relation to the surrounding medium (phase objects). We show a use of this technique to measure the refractive index (n) profile of waveguides produced by femtosecond laser micromachining inside the bulk of a sodalime glass. The results are used to analyze the influence of production parameters on n. The methodology requires only a bright-field optical microscope and has proved to be easily applied. Results provide important insights on the waveguide microfabrication process, since translation speed, rather than intensity, has shown to be more important for achieving greater variations in refractive indices. Index of refraction differences between the waveguide and the substrate of the order of 10-4 were measured for a series of straight waveguides fabricated with different parameters. Low sample scan speeds and pulse energies near 1.20 μJ used for fabrication showed the highest values of refractive index change for waveguides in sodalime glasses.
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10
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Bogris A, Wang J, Anyfantakis M, Loppinet B, Craig SL, Butt HJ, Fytas G. Solvent-Dependent Light-Induced Structures in Gem-Dichlorocyclopropanated Polybutadiene Solutions. J Phys Chem B 2018; 122:6995-7001. [PMID: 29890076 PMCID: PMC6122843 DOI: 10.1021/acs.jpcb.8b02463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
formation of permanent structures upon mild red laser illumination
in transparent polydiene solutions is examined in the case of gem-dichlorocyclopropanated
polybutadiene (gDCC-PB) polymers bearing 15% functional
units of the dichlorocyclopropane groups. The response was found to
be distinct from the precursor PB. Whereas fiber-like patterns were
clearly observed in both precursor and gDCC-PB solutions
in cyclohexane, these were absent in the case of gDCC-PB/chloroform but were present in the precursor PB/chloroform
solutions. The involved mechanical stresses were not sufficient for
the gDCC activation to be detected by NMR spectroscopy.
Remarkably, addition of even 10 wt % gDCC-PB into
the latter solution sufficed to suppress the light-induced patterning.
The importance of the chemical environment on the response to light
irradiation was further checked and confirmed by use of other PB copolymers.
Different diameter patterns and kinetics were observed. The strong
solvent and comonomer mediated effect was reflected neither in solvency
nor in optical polarizability differences of the polymers solvent
couples.
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Affiliation(s)
- A Bogris
- Institute of Electronic Structure and Laser , Foundation for Research and Technology - Hellas , 70013 Heraklion , Crete , Greece.,Department of Materials Science and Technology , University of Crete , 70013 Heraklion , Crete , Greece
| | - J Wang
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - M Anyfantakis
- Physics & Materials Science Research Unit , University of Luxembourg , 162a Avenue de la Faiencerie , Luxembourg L-1511 , Luxembourg
| | - B Loppinet
- Institute of Electronic Structure and Laser , Foundation for Research and Technology - Hellas , 70013 Heraklion , Crete , Greece
| | - S L Craig
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| | - H-J Butt
- Max-Planck Institute for Polymer Research , 55128 Mainz , Germany
| | - G Fytas
- Institute of Electronic Structure and Laser , Foundation for Research and Technology - Hellas , 70013 Heraklion , Crete , Greece.,Max-Planck Institute for Polymer Research , 55128 Mainz , Germany
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Bélanger E, Bérubé JP, de Dorlodot B, Marquet P, Vallée R. Comparative study of quantitative phase imaging techniques for refractometry of optical waveguides. OPTICS EXPRESS 2018; 26:17498-17510. [PMID: 30119561 DOI: 10.1364/oe.26.017498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A comparative study of quantitative phase imaging techniques for refractometry of optical waveguides is presented. Three techniques were examined: a method based on the transport-of-intensity equation, quadri-wave lateral shearing interferometry and digital holographic microscopy. The refractive index profile of a SMF-28 optical fiber was thoroughly characterized and served as a gold standard to assess the accuracy and precision of the phase imaging methods. Optical waveguides were inscribed in an Eagle2000 glass chip using a femtosecond laser and used to evaluate the sensitivity limit of these phase imaging approaches. It is shown that all three techniques provide accurate, repeatable and sensitive refractive index measurements. Using these phase imaging methods, we report a comprehensive map of the photosensitivity to femtosecond pulses of Eagle2000 glass. Finally, the reported data suggests that the phase imaging techniques are suited to be used as precise and non-destructive refractive index shift measuring tools to study and control the inscription process of optical waveguides.
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12
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Ramadan W, Wahba H, Shams El-Din M, Abd El-Sadek I. Refractive index retrieving of polarization maintaining optical fibers. OPTICAL FIBER TECHNOLOGY 2018; 40:69-75. [DOI: 10.1016/j.yofte.2017.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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13
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Bérubé JP, Vallée R. Femtosecond laser direct inscription of surface skimming waveguides in bulk glass. OPTICS LETTERS 2016; 41:3074-3077. [PMID: 27367105 DOI: 10.1364/ol.41.003074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a detailed study of waveguide inscription near the surface of bulk glass using a femtosecond laser. Three silicate glasses used extensively as hosts for photo-induced photonic devices were examined. Our results show that near-surface waveguides generally present a low-index contrast, as the pulse energy damage threshold decreases sharply at close proximity to the surface. We devised a novel method to allow the formation of optical waveguides that exhibit a high-index contrast up to the surface of any transparent material. As a proof of concept, the inscription of near-surface single-mode waveguides operating at a wavelength of 405 nm is demonstrated.
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14
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Demetriou G, Bérubé JP, Vallée R, Messaddeq Y, Petersen CR, Jain D, Bang O, Craig C, Hewak DW, Kar AK. Refractive index and dispersion control of ultrafast laser inscribed waveguides in gallium lanthanum sulphide for near and mid-infrared applications. OPTICS EXPRESS 2016; 24:6350-6358. [PMID: 27136826 DOI: 10.1364/oe.24.006350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The powerful ultrafast laser inscription technique is used to fabricate optical waveguides in gallium lanthanum sulphide substrates. For the first time the refractive index profile and the dispersion of such ultrafast laser inscribed waveguides are experimentally measured. In addition the Zero Dispersion Wavelength of both the waveguides and bulk substrate is experimentally determined. The Zero Dispersion Wavelength was determined to be between 3.66 and 3.71 μm for the waveguides and about 3.61 μm for the bulk. This work paves the way for realizing ultrafast laser inscribed waveguide devices in gallium lanthanum sulphide glasses for near and mid-IR applications.
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15
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Weng CJ, Hsu KY, Chen YF. Exploiting the image of the surface reflectivity to measure refractive index profiling for various optical fibers. OPTICS EXPRESS 2015; 23:11755-11762. [PMID: 25969266 DOI: 10.1364/oe.23.011755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A direct image method of surface reflectivities on a cleaved fiber end with a filtered halogen lamp and a TE-cooled CCD with high dynamic range is proposed to measure the multi-wavelength refractive index profiling (RIP). A polished black glass is used to be a reference standard for measuring the absolute reflectivity of the fiber end. With the developed calibration procedures, both the spatially dependent sensitivity and spectral responsivity of the CCD pixels can be eliminated to achieve the high spatial accuracy. Tested fiber is connected with a fiber terminator to prevent errors from the backside return light. With the present method, the RIP can be precisely measured for not only multi-mode fibers but also single-mode fibers.
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16
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Wang X, Ye Q, Sun T, Wang J, Deng Z, Mei J, Zhou W, Zhang C, Tian J. Two-dimensional scanning focused refractive-index microscopy and applications to refractive-index profiling of optical fibers. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:013702. [PMID: 25638085 DOI: 10.1063/1.4905179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The refractive-index profile (RIP) of optical fibers is of fundamental significance in determining critical fiber properties. Here, we present the application of a two-dimensional (2-D) scanning focused refractive-index microscopy (SFRIM) to accurately obtain the 2-D RIP of a graded-index optical fiber. Some modifications are made to SFRIM for better 2-D measurement. Quantitative RIP of the fiber is obtained with derivative total reflection method. The refractive-index accuracy is 0.002. The measured result is in good agreement with theoretical expectation. This method is straightforward, simple, repeatable, and free from signal distortion. This technique is suitable for symmetric and asymmetric optical fibers. The results indicate that this technique can be applied to obtain the RIPs of a wide range of materials and has broad application prospect in many fields.
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Affiliation(s)
- Xiaowan Wang
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Qing Ye
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Tengqian Sun
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jin Wang
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Zhichao Deng
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jianchun Mei
- Advanced Technology Institute, Nankai University, Tianjin 300071, China
| | - Wenyuan Zhou
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Chunping Zhang
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jianguo Tian
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
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17
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Jafarfard MR, Tayebi B, Lee S, Bae YS, Kim DY. Optimum phase shift for quantitative phase microscopy in volume measurement. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:2429-2436. [PMID: 25401354 DOI: 10.1364/josaa.31.002429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Volume measurement of a phase object is one of the most distinctive capabilities of quantitative phase microscopy (QPM). However, the accuracy of a measured volume is limited by the different noises of a measurement system and the finite bandpass filter used in the phase extraction algorithm. In this paper, we analyze the inherent errors in volume measurement with QPM and propose the optimum condition that can minimize these errors. We find that phase information of a sample in the frequency domain nonlinearly oscillates as a function of the phase shift corresponding to the sample and its medium, and that the phase information of a sample inside the bandpass filter can be maximized by a proper phase shift. Through numerical simulations and actual experiments, we demonstrate that the error in phase volume measurement can be effectively reduced by the enhancement of the phase signal inside the bandpass region using an optimum amount of phase, which can be controlled by changing either the medium index or the wavelength of illumination.
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18
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Bérubé JP, Messaddeq SH, Bernier M, Skripachev I, Messaddeq Y, Vallée R. Tailoring the refractive index of Ge-S based glass for 3D embedded waveguides operating in the mid-IR region. OPTICS EXPRESS 2014; 22:26103-16. [PMID: 25401643 DOI: 10.1364/oe.22.026103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The photosensitivity of GeS(x) binary glasses in response to irradiation to femtosecond pulses at 800 nm is investigated. Samples with three different molecular compositions were irradiated under different exposure conditions. The material response to laser exposure was characterized by both refractometry and micro-Raman spectroscopy. It is shown that the relative content of sulfur in the glass matrix influences the photo-induced refractive index modification. At low sulfur content, both positive and negative index changes can be obtained while at high sulfur content, only a positive index change can be reached. These changes were correlated with variations in the Raman response of exposed glass which were interpreted in terms of structural modifications of the glass network. Under optimized exposure conditions, waveguides with positive index changes of up to 7.8 x 10(-3)and a controllable diameter from 14 to 25 μm can be obtained. Direct inscription of low insertion losses (IL = 3.1 - 3.9 dB) waveguides is demonstrated in a sample characterized by a S/Ge ratio of 4. The current results open a pathway towards the use of Ge-S binary glasses for the fabrication of integrated mid-infrared photonic components.
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Schulze C, Wilde J, Brüning R, Schröter S, Duparré M. Measurement of effective refractive index differences in multimode optical fibers based on modal decomposition. OPTICS LETTERS 2014; 39:5810-5813. [PMID: 25361091 DOI: 10.1364/ol.39.005810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate the nondestructive measurement of the effective refractive index difference of two arbitrary modes within a multimode optical fiber by utilizing a tunable fiber grating. We use a mechanical grating of variable period to couple the respective modes and measure the mode content at the fiber output based on the correlation filter technique. From the dependence of the coupling efficiency on the grating period, the effective index difference of the modes can be extracted with high accuracy.
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Sun TQ, Ye Q, Wang XW, Wang J, Deng ZC, Mei JC, Zhou WY, Zhang CP, Tian JG. Scanning focused refractive-index microscopy. Sci Rep 2014; 4:5647. [PMID: 25008374 PMCID: PMC4090626 DOI: 10.1038/srep05647] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/23/2014] [Indexed: 11/09/2022] Open
Abstract
We present a novel scanning focused refractive-index microscopy (SFRIM) technique to obtain the refractive index (RI) profiles of objects. The method uses a focused laser as the light source, and combines the derivative total reflection method (DTRM), projection magnification, and scanning technique together. SFRIM is able to determine RIs with an accuracy of 0.002, and the central spatial resolution achieved is 1 µm, which is smaller than the size of the focal spot. The results of measurements carried out on cedar oil and a gradient-refractive-index (GRIN) lens agree well with theoretical expectations, verifying the accuracy of SFRIM. Furthermore, using SFRIM, to the best of our knowledge we have extracted for the first time the RI profile of a periodically modulated photosensitive gelatin sample. SFRIM is the first RI profile-resolved reflected light microscopy technique that can be applied to scattering and absorbing samples. SFRIM enables the possibility of performing RI profile measurements in a variety of applications, including optical waveguides, photosensitive materials and devices, photorefractive effect studies, and RI imaging in biomedical fields.
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Affiliation(s)
- Teng-Qian Sun
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Qing Ye
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Xiao-Wan Wang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jin Wang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Zhi-Chao Deng
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jian-Chun Mei
- Advanced Technology Institute, Nankai University, Tianjin 300071, China
| | - Wen-Yuan Zhou
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Chun-Ping Zhang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jian-Guo Tian
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
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21
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Hutsel MR, Gaylord TK. Concurrent three-dimensional characterization of the refractive-index and residual-stress distributions in optical fibers. APPLIED OPTICS 2012; 51:5442-5452. [PMID: 22859034 DOI: 10.1364/ao.51.005442] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 06/27/2012] [Indexed: 06/01/2023]
Abstract
A three-dimensional index-stress distribution (3DISD) measurement method for determining concurrently the refractive-index distributions (RIDs) and residual-stress distributions (RSDs) in optical fibers is presented. The method combines the quantitative-phase microscopy technique, the Brace-Köhler compensator technique, and computed tomography principles. These techniques are implemented on a common apparatus to enable concurrent characterization of the RID and the RSD. Measurements are performed on Corning SMF-28 fiber in an unperturbed section and in a section exposed to CO(2) laser radiation. The concurrent measurements allow for the first accurate comparison of the collocated RID and RSD. The resolutions of the refractive index and stress are estimated to be 2.34×10(-5) and 0.35 MPa, respectively.
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Affiliation(s)
- Michael R Hutsel
- School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250, USA
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22
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Messaddeq SH, Bérubé JP, Bernier M, Skripachev I, Vallée R, Messaddeq Y. Study of the photosensitivity of GeS binary glasses to 800 nm femtosecond pulses. OPTICS EXPRESS 2012; 20:2824-2831. [PMID: 22330518 DOI: 10.1364/oe.20.002824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present the first study of the photosensitivity of GeS binary glasses in response to irradiation to femtosecond pulses at 800 nm. A maximum positive refractive index change of 3.5x10(-3) is demonstrated with the possibility to control the waveguide diameter from ~8 to ~50 µm by adjusting the input pulse energy. It is also demonstrated that under different exposure conditions, a maximum negative index change of -7.5x10(-3) can be reached. The present results clearly illustrate the potential of this family of glasses for the fabrication of mid-infrared waveguides.
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Affiliation(s)
- S H Messaddeq
- Centre d’optique, photonique et laser (COPL), Université Laval, Québec G1V 0A6, Canada.
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Frank J, Matrisch J, Horstmann J, Altmeyer S, Wernicke G. Refractive index determination of transparent samples by noniterative phase retrieval. APPLIED OPTICS 2011; 50:427-33. [PMID: 21283231 DOI: 10.1364/ao.50.000427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We present a simple method to determine the refractive indices of transparent specimens. The refractive index of an object under investigation is received by evaluating the optical path difference introduced by the object, while taking into account geometric parameters. The optical path difference that corresponds to the phase distribution is obtained by a noninterferometric, noniterative phase retrieval method based on Green's functions. It will be shown that this technique is a highly accurate and quantitative method for refractive index determination.
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Affiliation(s)
- Johannes Frank
- Institute of Applied Optics and Electronics, Cologne University of Applied Sciences, Cologne, Germany. johannes.frank@fh‐koeln.de
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24
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Singh K, Dion C, Lesk MR, Ozaki T, Costantino S. Spectral-domain phase microscopy with improved sensitivity using two-dimensional detector arrays. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:023706. [PMID: 21361600 DOI: 10.1063/1.3556787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work we demonstrate the use of two-dimensional detectors to improve the signal-to-noise ratio (SNR) and sensitivity in spectral-domain phase microscopy for subnanometer accuracy measurements. We show that an increase in SNR can be obtained, from 82 dB to 105 dB, using 150 pixel lines of a low-cost CCD camera as compared to a single line, to compute an averaged axial scan. In optimal mechanical conditions, phase stability as small as 92 μrad, corresponding to 6 pm displacement accuracy, could be obtained. We also experimentally demonstrate the benefit of spatial-averaging in terms of the reduction of signal fading due to an axially moving sample. The applications of the improved system are illustrated by imaging live cells in culture.
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Affiliation(s)
- K Singh
- Centre de Recherche, Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
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25
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Rinehart MT, Shaked NT, Jenness NJ, Clark RL, Wax A. Simultaneous two-wavelength transmission quantitative phase microscopy with a color camera. OPTICS LETTERS 2010; 35:2612-4. [PMID: 20680075 DOI: 10.1364/ol.35.002612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We present a quantitative phase microscopy method that uses a Bayer mosaic color camera to simultaneously acquire off-axis interferograms in transmission mode at two distinct wavelengths. Wrapped phase information is processed using a two-wavelength algorithm to extend the range of the optical path delay measurements that can be detected using a single temporal acquisition. We experimentally demonstrate this technique by acquiring the phase profiles of optically clear microstructures without 2pi ambiguities. In addition, the phase noise contribution arising from spectral channel crosstalk on the color camera is quantified.
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Affiliation(s)
- Matthew T Rinehart
- Department of Biomedical Engineering, Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, USA.
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26
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Allsop T, Dubov M, Mezentsev V, Bennion I. Inscription and characterization of waveguides written into borosilicate glass by a high-repetition-rate femtosecond laser at 800 nm. APPLIED OPTICS 2010; 49:1938-1950. [PMID: 20357880 DOI: 10.1364/ao.49.001938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A series of waveguides was inscribed in a borosilicate glass (BK7) by an 11 MHz repetition rate femtosecond laser operating with pulse energies from 16 to 30 nJ and focused at various depths within the bulk material. The index modification was measured using a quantitative phase microscopy technique that revealed central index changes ranging from 5 x 10(-3) to 10(-2), leading to waveguides that exhibited propagation losses of 0.2 dB/cm at a wavelength of 633 nm and 0.6 dB/cm at a wavelength of 1550 nm with efficient mode matching, less than 0.2 dB, to standard optical fibers. Analysis of the experimental data shows that, for a given inscription energy, the index modification has a strong dependence on inscription scanning velocity. At higher energies, the index modification increases with increasing inscription scanning velocity with other fabrication parameters constant.
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Affiliation(s)
- Thomas Allsop
- Photonics Research Group, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom.
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27
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Blanc W, Dussardier B, Monnom G, Peretti R, Jurdyc AM, Jacquier B, Foret M, Roberts A. Erbium emission properties in nanostructured fibers. APPLIED OPTICS 2009; 48:G119-G124. [PMID: 19881631 DOI: 10.1364/ao.48.00g119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new route was recently proposed to modify some spectroscopic properties of rare-earth ions in silica-based fibers. We had shown the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in fiber preforms. Here we present the achieved stabilization of nanometric erbium-doped dielectric nanoparticles within the core of silica fibers. We present the nanoparticle dimensional characterization in fiber samples. We also show the spectroscopic characterization of erbium in preform samples with similar nanoparticle size and composition. This new route could have important potentials in improving rare-earth-doped fiber amplifiers and laser sources.
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Affiliation(s)
- Wilfried Blanc
- Université de Nice-Sophia Antipolis, CNRS/LPMC, Nice, France
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28
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Ampem-Lassen E, Simpson DA, Gibson BC, Trpkovski S, Hossain FM, Huntington ST, Ganesan K, Hollenberg LCL, Prawer S. Nano-manipulation of diamond-based single photon sources. OPTICS EXPRESS 2009; 17:11287-11293. [PMID: 19582042 DOI: 10.1364/oe.17.011287] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The ability to manipulate nano-particles at the nano-scale is critical for the development of active quantum systems. This paper presents a technique to manipulate diamond nano-crystals at the nano-scale using a scanning electron microscope, nano-manipulator and custom tapered optical fibre probes. The manipulation of a approximately 300 nm diamond crystal, containing a single nitrogen-vacancy centre, onto the endface of an optical fibre is demonstrated. The emission properties of the single photon source post manipulation are in excellent agreement with those observed on the original substrate.
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Affiliation(s)
- E Ampem-Lassen
- Quantum Communications Victoria, School of Physics, The University of Melbourne, Parkville 3010, Australia
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29
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Kouskousis B, Kitcher DJ, Collins S, Roberts A, Baxter GW. Quantitative phase and refractive index analysis of optical fibers using differential interference contrast microscopy. APPLIED OPTICS 2008; 47:5182-5189. [PMID: 18830309 DOI: 10.1364/ao.47.005182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A systematic and straightforward image processing method to extract quantitative phase and refractive index data from weak phase objects is presented, obtained using differential interference contrast (DIC) microscopy. The method is demonstrated on DIC images of optical fibers where a directional integration routine is applied to the DIC images to extract phase and refractive index information using the data obtained across the whole DIC image. By applying the inverse Abel transform to the resultant phase images, an accurate refractive index profile is obtained. The method presented here is compared to the refracted near-field technique, typically used to obtain the refractive index profile of optical fibers, and shows excellent agreement. It is concluded that through careful image processing procedures, DIC microscopy can be successfully implemented to obtain quantitative phase and refractive index information of optical fibers.
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Affiliation(s)
- Betty Kouskousis
- Optical Technology Research Laboratory, Centre for Telecommunications and Microelectronics, Victoria University, P.O. Box 14428, Melbourne, Victoria 8001, Australia.
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30
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Ampem-Lassen E, Sidiroglou F, Peng JL, Huntington ST, Roberts A. Index mapping for fibres with symmetric and asymmetric refractive index profiles. OPTICS EXPRESS 2008; 16:10912-10917. [PMID: 18648404 DOI: 10.1364/oe.16.010912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 07/01/2008] [Indexed: 05/26/2023]
Abstract
The application of phase imaging to refractive index profiling of an optical fiber slice is described. It is shown that the refractive index profile of axially symmetric and asymmetric optical fibers can be obtained from quantitative phase image of thin transverse optical fiber slices. Although this method requires careful and time consuming sample preparation, one advantage of this technique is that it can be applied to a wide range of optical fibers. In this paper results for both symmetric and non-symmetric fibers are presented and good agreement with the industry-standard refracted near-field technique demonstrated.
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31
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Hutsel MR, Montarou CC, Dachevski AI, Gaylord TK. Algorithm performance in the determination of the refractive-index profile of optical fibers. APPLIED OPTICS 2008; 47:760-767. [PMID: 18288224 DOI: 10.1364/ao.47.000760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Three algorithms for computing the refractive-index profile of azimuthally symmetric optical fibers via the inverse Abel transform are compared to determine their relative accuracies. Appropriate values of algorithm parameters are also determined. The direct differentiation algorithm, the iterative algorithm, and the Fourier algorithm are used to calculate the refractive-index profile from simulated measurements of the phase shift of light transmitted transversely through the fiber. The rms error in the calculated index profile is used to quantify the accuracy of each algorithm. The Fourier algorithm is typically the most accurate of the three.
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Affiliation(s)
- Michael R Hutsel
- School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive, N.W., Atlanta, Georgia 30332-0250, USA
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32
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Dragomir NM, Goh XM, Roberts A. Three-dimensional refractive index reconstruction with quantitative phase tomography. Microsc Res Tech 2007; 71:5-10. [PMID: 17886342 DOI: 10.1002/jemt.20520] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Optical tomography based on quantitative phase microscopy is used to determine nondestructively and with high spatial resolution the three-dimensional (3D) refractive index distributions within optical fiber devices. After obtaining a series of phase images of the fiber as it is rotated around its longitudinal axis at regularly-spaced angular positions, filtered backprojection is used to reconstruct a 3D map of the refractive index. The 3D refractive index distribution of the join region between two fusion spliced optical fibers is reconstructed with accuracy better than 10(-3).
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Affiliation(s)
- N M Dragomir
- School of Physics, The University of Melbourne, Parkville 3010, Victoria, Australia.
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33
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Dragomir NM, Ampen-Lassen E, Baxter GW, Pace P, Huntington ST, Farrell PM, Stevenson AJ, Roberts A. Analysis of changes in optical fibers during arc-fusion splicing by use of quantitative phase imaging. Microsc Res Tech 2006; 69:847-51. [PMID: 17029239 DOI: 10.1002/jemt.20357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A non-interferometric imaging technique in conjunction with Abel inversion is used to directly and quantitatively examine the changes in optical fibers due to the heating produced during arc-fusion splicing as a function of fusion arc parameters. Phase images in the vicinity of a fusion splice are obtained using Quantitative Phase Microscopy, allowing the refractive-index change to be reconstructed with high spatial resolution. This simple, nondestructive method confirms that, for a fixed arc current, while the fusion time increases, the refractive-index of both fiber cores within the fusion region decreases in magnitude, the core region broadens, and the axial gradient decreases.
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Affiliation(s)
- N M Dragomir
- School of Physics, The University of Melbourne, Victoria 3010, Australia.
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34
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Liu JH, Yang PC, Chiu YH. Fabrication of high-performance, gradient-refractive-index plastic rods with surfmer-cluster-stabilized nanoparticles. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21682] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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35
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Dragomir N, Baxter G, Roberts A. Phase-sensitive imaging techniques applied to optical fibre characterisation. ACTA ACUST UNITED AC 2006. [DOI: 10.1049/ip-opt:20050105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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36
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Joo C, Akkin T, Cense B, Park BH, de Boer JF. Spectral-domain optical coherence phase microscopy for quantitative phase-contrast imaging. OPTICS LETTERS 2005; 30:2131-3. [PMID: 16127933 DOI: 10.1364/ol.30.002131] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We describe a novel microscopy technique for quantitative phase-contrast imaging of a transparent specimen. The technique is based on depth-resolved phase information provided by common path spectral-domain optical coherence tomography and can measure minute phase variations caused by changes in refractive index and thickness inside the specimen. We demonstrate subnanometer level path-length sensitivity and present images obtained on reflection from a known phase object and human epithelial cheek cells.
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Affiliation(s)
- Chulmin Joo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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37
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Curl CL, Bellair CJ, Harris T, Allman BE, Harris PJ, Stewart AG, Roberts A, Nugent KA, Delbridge LMD. Refractive index measurement in viable cells using quantitative phase-amplitude microscopy and confocal microscopy. Cytometry A 2005; 65:88-92. [PMID: 15800856 DOI: 10.1002/cyto.a.20134] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The refractive index (RI) of cellular material provides fundamental biophysical information about the composition and organizational structure of cells. Efforts to describe the refractive properties of cells have been significantly impeded by the experimental difficulties encountered in measuring viable cell RI. In this report we describe a procedure for the application of quantitative phase microscopy in conjunction with confocal microscopy to measure the RI of a cultured muscle cell specimen. METHODS The experimental strategy involved calculation of cell thickness by using confocal optical sectioning procedures, construction of a phase map of the same cell using quantitative phase microscopy, and selection of cellular regions of interest to solve for the cell RI. RESULTS Mean cell thickness and phase values for six cell regions (five cytoplasmic and one nuclear) were determined. The average refractive index calculated for cytoplasmic and nuclear regions was 1.360 +/- 0.004. The uncertainty in the final RI value represents the technique measurement error. CONCLUSIONS The methodology we describe for viable cell RI measurement with this prototype cell has broad generic application in the study of cell growth and functional responses. The RI value we report may be used in optical analyses of cultured cell structure and morphology.
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Affiliation(s)
- Claire L Curl
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
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38
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Liu JH, Wu DS, Tseng KY. Fabrication and Characterization of GRIN Plastic Rods Containing Silver Nanoparticles with Novel Surfmers. MACROMOL CHEM PHYS 2004. [DOI: 10.1002/macp.200400197] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Sherman GW, Bradley CC. Interferometric laser diode probing of micrometer- and nanometer-scale materials. APPLIED OPTICS 2003; 42:6360-6366. [PMID: 14649279 DOI: 10.1364/ao.42.006360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We are developing a method for real-time detection, tracking, and categorization of micrometer- and nanometer-scale particles and materials using light scattered from a swept standing-wave probe. Synchronous, phase-sensitive detection of the weakly scattered optical field is exploited to provide interferometric sensitivity and improve the signal-to-noise ratio, allowing use of low-power laser diode sources and photodiode detectors. To demonstrate the technique, we probe a set of W, C, and Cu microfibers and determine diameters and refractive-index values from a detailed comparison of light-scattering data and a numerical model. We extrapolate these results and discuss the application of laser diode sources and photodiode receivers for the detection and study of nanoscale materials.
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Affiliation(s)
- Gregory W Sherman
- Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, Texas 76129, USA
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