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Klufts M, Jiménez AM, Lotz S, Bashir MA, Pfeiffer T, Mlynek A, Wieser W, Chamorovskiy A, Bradu A, Podoleanu A, Huber R. 828 kHz retinal imaging with an 840 nm Fourier domain mode locked laser. BIOMEDICAL OPTICS EXPRESS 2023; 14:6493-6508. [PMID: 38420314 PMCID: PMC10898573 DOI: 10.1364/boe.504302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/08/2023] [Accepted: 11/16/2023] [Indexed: 03/02/2024]
Abstract
This paper presents a Fourier domain mode locked (FDML) laser centered around 840 nm. It features a bidirectional sweep repetition rate of 828 kHz and a spectral bandwidth of 40 nm. An axial resolution of ∼9.9 µm in water and a 1.4 cm sensitivity roll-off are achieved. Utilizing a complex master-slave (CMS) recalibration method and due to a sufficiently high sensitivity of 84.6 dB, retinal layers of the human eye in-vivo can be resolved during optical coherence tomography (OCT) examination. The developed FDML laser enables acquisition rates of 3D-volumes with a size of 200 × 100 × 256 voxels in under 100 milliseconds. Detailed information on the FDML implementation, its challenging design tasks, and OCT images obtained with the laser are presented in this paper.
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Affiliation(s)
- Marie Klufts
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
| | | | - Simon Lotz
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
| | | | | | | | | | | | - Adrian Bradu
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Adrian Podoleanu
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Robert Huber
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
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2
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Ma Y, Li C, Jiang H, Zhao Y, Liu J, Yu Y, Wang Y, Shi W, Ma Z. OCT based four-dimensional cardiac imaging of a living chick embryo using an impedance signal as a gating for post-acquisition synchronization. BIOMEDICAL OPTICS EXPRESS 2022; 13:6595-6609. [PMID: 36589591 PMCID: PMC9774874 DOI: 10.1364/boe.476254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Optical coherence tomography (OCT) is a non-invasive imaging modality with high spatial resolution suitable for early embryonic heart imaging. However, the most commonly used OCT systems cannot provide direct 4-D imaging due to acquisition speed limitations. We proposed a retrospective gating 4-D reconstruction method based on spectral domain OCT. A special circuit was designed to measure the impedance change of chick embryos in response to the heart beating. The impedance signal was acquired simultaneously with the OCT B-scan image sequence at several different locations along the heart. The impedance signal was used as a gating for 4-D reconstruction. The reconstruction algorithm includes cardiac period calculation, interpolation from multi-cardiac cycle image sequence into one cardiac cycle, and cardiac phase synchronization among the different locations of the heart. The synchronism of the impedance signal change with the heartbeat was verified. Using the proposed method, we reconstructed the cardiac outflow tract (OFT) of chick embryos at an early stage of development (Hamburger-Hamilton stage 18). We showed that the reconstructed 4-D images correctly captured the dynamics of the OFT wall motion.
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Affiliation(s)
- Yushu Ma
- School of Computer Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Chuanxi Li
- Hangzhou Xinrui Medical Technology Co., Ltd, No. 22 Xinyan Road, Hangzhou 311100, China
| | - Huiwen Jiang
- College of Information Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Yuqian Zhao
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Jian Liu
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Yao Yu
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Yi Wang
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Wenbo Shi
- School of Computer Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Zhenhe Ma
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
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3
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Huang D, Shi Y, Li F, Wai PKA. Fourier Domain Mode Locked Laser and Its Applications. SENSORS 2022; 22:s22093145. [PMID: 35590839 PMCID: PMC9105910 DOI: 10.3390/s22093145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/05/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022]
Abstract
The sweep rate of conventional short-cavity lasers with an intracavity-swept filter is limited by the buildup time of laser signals from spontaneous emissions. The Fourier domain mode-locked (FDML) laser was proposed to overcome the limitations of buildup time by inserting a long fiber delay in the cavity to store the whole swept signal and has attracted much interest in both theoretical and experimental studies. In this review, the theoretical models to understand the dynamics of the FDML laser and the experimental techniques to realize high speed, wide sweep range, long coherence length, high output power and highly stable swept signals in FDML lasers will be discussed. We will then discuss the applications of FDML lasers in optical coherence tomography (OCT), fiber sensing, precision measurement, microwave generation and nonlinear microscopy.
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Affiliation(s)
- Dongmei Huang
- Photonics Research Institute, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (D.H.); (Y.S.)
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
| | - Yihuan Shi
- Photonics Research Institute, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (D.H.); (Y.S.)
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
| | - Feng Li
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
- Photonics Research Institute, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Correspondence:
| | - P. K. A. Wai
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
- Photonics Research Institute, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Department of Physics, Hong Kong Baptist University, Hong Kong, China
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4
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Luo S, Ran Y, Liu L, Huang H, Tang X, Fan Y. Classification of gastric cancerous tissues by a residual network based on optical coherence tomography images. Lasers Med Sci 2022; 37:2727-2735. [PMID: 35344109 DOI: 10.1007/s10103-022-03546-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 03/10/2022] [Indexed: 11/26/2022]
Abstract
Optical coherence tomography (OCT) is a noninvasive, radiation-free, and high-resolution imaging technology. The intraoperative classification of normal and cancerous tissue is critical for surgeons to guide surgical operations. Accurate classification of gastric cancerous OCT images is beneficial to improve the effect of surgical treatment based on the deep learning method. The OCT system was used to collect images of cancerous tissues removed from patients. An intelligent classification method of gastric cancerous tissues based on the residual network is proposed in this study and optimized with the ResNet18 model. Four residual blocks are used to reset the model structure of ResNet18 and reduce the number of network layers to identify cancerous tissues. The model performance of different residual networks is evaluated by accuracy, precision, recall, specificity, F1 value, ROC curve, and model parameters. The classification accuracies of the proposed method and ResNet18 both reach 99.90%. Also, the model parameters of the proposed method are 44% of ResNet18, which occupies fewer system resources and is more efficient. In this study, the proposed deep learning method was used to automatically recognize OCT images of gastric cancerous tissue. This artificial intelligence method could help promote the clinical application of gastric cancerous tissue classification in the future.
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Affiliation(s)
- Site Luo
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Yuchen Ran
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Lifei Liu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Huihui Huang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Xiaoying Tang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
- Institute of Engineering Medicine, Beijing Institute of Technology, Beijing, 100081, China
| | - Yingwei Fan
- Institute of Engineering Medicine, Beijing Institute of Technology, Beijing, 100081, China.
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Göb M, Pfeiffer T, Draxinger W, Lotz S, Kolb JP, Huber R. Continuous spectral zooming for in vivo live 4D-OCT with MHz A-scan rates and long coherence. BIOMEDICAL OPTICS EXPRESS 2022; 13:713-727. [PMID: 35284187 PMCID: PMC8884208 DOI: 10.1364/boe.448353] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
We present continuous three-dimensional spectral zooming in live 4D-OCT using a home-built FDML based OCT system with 3.28 MHz A-scan rate. Improved coherence characteristics of the FDML laser allow for imaging ranges up to 10 cm. For the axial spectral zoom feature, we switch between high resolution and long imaging range by adjusting the sweep range of our laser. We present a new imaging setup allowing for synchronized adjustments of the imaging range and lateral field of view during live OCT imaging. For this, a novel inline recalibration algorithm was implemented that enables numerical k-linearization of the raw OCT fringes for every frame instead of every volume. This is realized by acquiring recalibration data within the dead time of the raster scan at the turning points of the fast axis scanner. We demonstrate in vivo OCT images of fingers and hands at different resolution modes and show real three-dimensional zooming during live 4D-OCT. A three-dimensional spectral zooming feature for live 4D-OCT is expected to be a useful tool for a wide range of biomedical, scientific and research applications, especially in OCT guided surgery.
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Affiliation(s)
- Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Simon Lotz
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye. Sci Rep 2022; 12:992. [PMID: 35046423 PMCID: PMC8770693 DOI: 10.1038/s41598-022-04784-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/13/2021] [Indexed: 11/24/2022] Open
Abstract
This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but also enables volumetric OCT for comprehensive structural analysis and OCT angiography (OCTA) for visualizing vasculature. The 15.5 mm (~ 11.6 mm in tissue) depth range spans all optical surfaces from the anterior cornea to the posterior lens capsule. The 1310 nm wavelength range enables structural OCT and OCTA deep in the sclera and through the iris. Achieving high speed and long range requires linearizing the VCSEL wavenumber sweep to efficiently utilize analog-to-digital conversion bandwidth. Dual channel recording of the OCT and calibration interferometer fringe signals, as well as sweep to sweep wavenumber compensation, is used to achieve invariant 12.2 µm (~ 9.1 µm in tissue) axial resolution and optimum point spread function throughout the depth range. Dynamic focusing using a tunable liquid lens extends the effective depth of field while preserving the lateral resolution. Improved optical and mechanical design, including parallax “split view” iris cameras and stable, ergonomic patient interface, facilitates accurate instrument positioning, reduces patient motion, and leads to improved imaging data yield and measurement accuracy. We present structural and angiographic OCT images of the anterior eye, demonstrating the unique imaging capabilities using representative scanning protocols which may be relevant to future research and clinical applications.
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Pfeiffer T, Göb M, Draxinger W, Karpf S, Kolb JP, Huber R. Flexible A-scan rate MHz-OCT: efficient computational downscaling by coherent averaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:6799-6811. [PMID: 33282524 PMCID: PMC7687947 DOI: 10.1364/boe.402477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 05/29/2023]
Abstract
In order to realize adjustable A-scan rates of fast optical coherence tomography (OCT) systems, we investigate averaging of OCT image data acquired with a MHz-OCT system based on a Fourier Domain Mode Locked (FDML) laser. Increased system sensitivity and image quality can be achieved with the same system at the cost of lower imaging speed. Effectively, the A-scan rate can be reduced in software by a freely selectable factor. We demonstrate a detailed technical layout of the strategies necessary to achieve efficient coherent averaging. Since there are many new challenges specific to coherent averaging in swept source MHz-OCT, we analyze them point by point and describe the appropriate solutions. We prove that coherent averaging is possible at MHz OCT-speed without special interferometer designs or digital phase stabilization. We find, that in our system up to ∼100x coherent averaging is possible while achieving a sensitivity increase close to the ideal values. This corresponds to a speed reduction from 3.3 MHz to 33 kHz and a sensitivity gain of 20 dB. We show an imaging comparison between coherent and magnitude averaging of a human finger knuckle joint in vivo with 121 dB sensitivity for the coherent case. Further, the benefits of computational downscaling in low sensitivity MHz-OCT systems are analyzed.
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Affiliation(s)
- Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Sebastian Karpf
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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8
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High Speed, Localized Multi-Point Strain Measurements on a Containment Vessel at 1.7 MHz Using Swept-Wavelength Laser-Interrogated Fiber Bragg Gratings. SENSORS 2020; 20:s20205935. [PMID: 33092311 PMCID: PMC7589595 DOI: 10.3390/s20205935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 11/17/2022]
Abstract
Dynamic elastic strain in ~1.8 and 1.0 m diameter containment vessels containing a high explosive detonation was measured using an array of fiber Bragg gratings. The all-optical method, called real-time localized strain measurement, recorded the strain for 10 ms after detonation with additional measurements being sequentially made at a rate of 1.7 MHz. A swept wavelength laser source provided the repetition rate necessary for such high-speed measurements while also providing enough signal strength and bandwidth to simultaneously measure 8 or more unique points on the vessel’s surface. The data presented here arethen compared with additional diagnostics consisting of a fast spectral interferometer and an optical backscatter reflectometer to show a comparison between the local and global changes in the vessel strain, both dynamically and statically to further characterize the performance of the localized strain measurement. The results are also compared with electrical resistive strain gauges and finite element analysis simulations.
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9
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Karpf S, Jalali B. Fourier-domain mode-locked laser combined with a master-oscillator power amplifier architecture. OPTICS LETTERS 2019; 44:1952-1955. [PMID: 30985783 DOI: 10.1364/ol.44.001952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/15/2019] [Indexed: 06/09/2023]
Abstract
Originally introduced in 2005 for high-speed optical coherence tomography, the rapidly wavelength-swept Fourier-domain mode-locked (FDML) laser still, to this day, enables highest imaging speeds through a very high-speed spectral tuning capability. The FDML laser achieves a tuning bandwidth of over 1/10th of its center wavelength and can sweep this entire bandwidth in less than a microsecond. Interestingly, even though it covers a very broad spectral range, instantaneously it has a narrow spectral linewidth that puts it in a unique space compared to other high-speed broadband laser sources, e.g., mode-locked lasers or supercontinuum sources. Although it has been applied for nonlinear Raman spectroscopy and imaging, a current drawback of this continuous wave laser is the relatively low instantaneous power of 10-100 mW. Here, we report the combination of an FDML laser with a master oscillator power amplifier (MOPA) architecture to increase the instantaneous power of the FDML for nonlinear optical interactions. The output of an FDML laser around 1060 nm is modulated to short pulses by using an electro-optic amplitude modulator and subsequently amplified using ytterbium-doped fiber amplifiers (YDFAs). This generates a spectral rainbow of 65 picosecond pulses, where each pulse has a distinct, monochromatic wavelength. The instantaneous power can be adjusted by the YDFAs to reach nonlinear optical excitation regimes. This wavelength-swept FDML-MOPA laser will have a vast range of applications in, e.g., nonlinear optics, spectroscopy, imaging, and sensing.
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10
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Lippok N, Siddiqui M, Vakoc BJ, Bouma BE. Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging. PHYSICAL REVIEW APPLIED 2019; 11:10.1103/physrevapplied.11.014018. [PMID: 32051835 PMCID: PMC7013993 DOI: 10.1103/physrevapplied.11.014018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fourier domain mode-locking (FDML) has been a popular laser design for high speed optical frequency domain imaging (OFDI) but the achievable coherence length, and therefore imaging range, has been limited. The narrow instantaneous linewidth of a frequency comb (FC) FDML laser could provide an attractive platform for high speed as well as long range OFDI. Unfortunately, aliasing artifacts arising from signals beyond the principle measurement depth of the free spectral range have prohibited the use of a FC FDML for imaging so far. To make the enhanced coherence length of FC FDML laser available, methods to manage such artifacts are required. Recently, coherent circular ranging has been demonstrated that uses frequency combs for imaging in much reduced RF bandwidths. Here, we revisit circular ranging as a tool of making the long coherence length of an FDML frequency comb laser as well as its use for tissue imaging accessible. Using an acousto-optic frequency shifter (AOFS), we describe an active method to mitigate signal aliasing that is both stable and wavelength independent. We show that an FC FDML laser offers an order of magnitude improved coherence length compared to traditional FDML laser designs without requiring precise dispersion engineering. We discuss design parameters of a frequency stepping laser resonator as well as aliasing from a frequency comb and AOFS in OFDI with numerical simulations. The use of circular ranging additionally reduced acquisition bandwidths 15-fold compared with traditional OFDI methods. The FC FDML/AOFS design offers a convenient platform for long range and high speed imaging as well as exploring signal and image processing methods in circular ranging.
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Affiliation(s)
- Norman Lippok
- Harvard Medical School, Boston, MA 02115, USA
- Wellman Center for Photomedicine, Massachusetts General
Hospital, Boston, MA 02114, USA
| | - Meena Siddiqui
- Harvard Medical School, Boston, MA 02115, USA
- Wellman Center for Photomedicine, Massachusetts General
Hospital, Boston, MA 02114, USA
| | - Benjamin J. Vakoc
- Harvard Medical School, Boston, MA 02115, USA
- Wellman Center for Photomedicine, Massachusetts General
Hospital, Boston, MA 02114, USA
- Institute for Medical Engineering and Science,
Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Brett E. Bouma
- Harvard Medical School, Boston, MA 02115, USA
- Wellman Center for Photomedicine, Massachusetts General
Hospital, Boston, MA 02114, USA
- Institute for Medical Engineering and Science,
Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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11
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Pfeiffer T, Petermann M, Draxinger W, Jirauschek C, Huber R. Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:4130-4148. [PMID: 30615700 PMCID: PMC6157755 DOI: 10.1364/boe.9.004130] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/16/2018] [Accepted: 07/16/2018] [Indexed: 05/28/2023]
Abstract
We investigate the origin of high frequency noise in Fourier domain mode locked (FDML) lasers and present an extremely well dispersion compensated setup which virtually eliminates intensity noise and dramatically improves coherence properties. We show optical coherence tomography (OCT) imaging at 3.2 MHz A-scan rate and demonstrate the positive impact of the described improvements on the image quality. Especially in highly scattering samples, at specular reflections and for strong signals at large depth, the noise in optical coherence tomography images is significantly reduced. We also describe a simple model that suggests a passive physical stabilizing mechanism that leads to an automatic compensation of remaining cavity dispersion in FDML lasers.
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Affiliation(s)
- Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | | | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Christian Jirauschek
- Department of Electrical and Computer Engineering, Technical University of Munich (TUM), Arcisstraße 21, 80333 Munich, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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12
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Elahi S, Gu S, Thrane L, Rollins AM, Jenkins MW. Complex regression Doppler optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-8. [PMID: 29704328 PMCID: PMC5920204 DOI: 10.1117/1.jbo.23.4.046009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/09/2018] [Indexed: 05/06/2023]
Abstract
We introduce a new method to measure Doppler shifts more accurately and extend the dynamic range of Doppler optical coherence tomography (OCT). The two-point estimate of the conventional Doppler method is replaced with a regression that is applied to high-density B-scans in polar coordinates. We built a high-speed OCT system using a 1.68-MHz Fourier domain mode locked laser to acquire high-density B-scans (16,000 A-lines) at high enough frame rates (∼100 fps) to accurately capture the dynamics of the beating embryonic heart. Flow phantom experiments confirm that the complex regression lowers the minimum detectable velocity from 12.25 mm / s to 374 μm / s, whereas the maximum velocity of 400 mm / s is measured without phase wrapping. Complex regression Doppler OCT also demonstrates higher accuracy and precision compared with the conventional method, particularly when signal-to-noise ratio is low. The extended dynamic range allows monitoring of blood flow over several stages of development in embryos without adjusting the imaging parameters. In addition, applying complex averaging recovers hidden features in structural images.
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Affiliation(s)
- Sahar Elahi
- Case Western Reserve University, Department of Pediatrics, Cleveland, Ohio, United States
| | - Shi Gu
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
| | - Lars Thrane
- Case Western Reserve University, Department of Pediatrics, Cleveland, Ohio, United States
| | - Andrew M. Rollins
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
| | - Michael W. Jenkins
- Case Western Reserve University, Department of Pediatrics, Cleveland, Ohio, United States
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
- Address all correspondence to: Michael W. Jenkins, E-mail:
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13
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Kolb JP, Pfeiffer T, Eibl M, Hakert H, Huber R. High-resolution retinal swept source optical coherence tomography with an ultra-wideband Fourier-domain mode-locked laser at MHz A-scan rates. BIOMEDICAL OPTICS EXPRESS 2018; 9:120-130. [PMID: 29359091 PMCID: PMC5772568 DOI: 10.1364/boe.9.000120] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 05/13/2023]
Abstract
We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with a record 143 nm sweep bandwidth at 2∙ 417 kHz = 834 kHz and 120 nm at 1.67 MHz, respectively. We show that not only the bandwidth alone, but also the shape of the spectrum is critical for the resulting axial resolution, because of the specific wavelength-dependent absorption of the vitreous. The theoretical limit of our setup lies at 5.9 µm axial resolution. In vivo MHz-OCT imaging of human retina is performed and the image quality is compared to the previous results acquired with 70 nm sweep range, as well as to existing spectral domain OCT data with 2.1 µm axial resolution from literature. We identify benefits of the higher resolution, for example the improved visualization of small blood vessels in the retina besides several others.
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14
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Klein T, Huber R. High-speed OCT light sources and systems [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:828-859. [PMID: 28270988 PMCID: PMC5330584 DOI: 10.1364/boe.8.000828] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 05/18/2023]
Abstract
Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.
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Affiliation(s)
- Thomas Klein
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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15
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Wan M, Wang L, Li F, Cao Y, Wang X, Feng X, Guan BO, Wai PKA. Rapid, k-space linear wavelength scanning laser source based on recirculating frequency shifter. OPTICS EXPRESS 2016; 24:27614-27621. [PMID: 27906332 DOI: 10.1364/oe.24.027614] [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 propose and successfully demonstrate a k-space linear and self-clocked wavelength scanning fiber laser source based on recirculating frequency shifting (RFS). The RFS is realized with a high speed electro-optic dual parallel Mach-Zehnder modulator operating at the state of carrier suppressed single sideband modulation. A gated short pulse is injected into an amplified RFS loop to generate the wavelength scanning pulse train. We find that the accumulation of in-band amplified spontaneous emission (ASE) noise over multiple scanning periods will saturate the erbium-doped fiber amplifier and impede the amplification to the pulse signal in the RFS loop. To overcome the degradation of temporal signal due to the accumulation of ASE noise over multiple scanning periods, we insert a modulated optical switch into the RFS loop to completely attenuate the in-band ASE noise at the end of each scanning period. The signal to noise ratio of the temporal pulsed signal is greatly enhanced. K-space linear and self-clocked wavelength scanning fiber laser sources in 6.1 nm/7.2 nm scanning range with 20 GHz/30 GHz frequency shifting are successfully demonstrated.
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16
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Men J, Huang Y, Solanki J, Zeng X, Alex A, Jerwick J, Zhang Z, Tanzi RE, Li A, Zhou C. Optical Coherence Tomography for Brain Imaging and Developmental Biology. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2016; 22:6803213. [PMID: 27721647 PMCID: PMC5049888 DOI: 10.1109/jstqe.2015.2513667] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT) is a promising research tool for brain imaging and developmental biology. Serving as a three-dimensional optical biopsy technique, OCT provides volumetric reconstruction of brain tissues and embryonic structures with micrometer resolution and video rate imaging speed. Functional OCT enables label-free monitoring of hemodynamic and metabolic changes in the brain in vitro and in vivo in animal models. Due to its non-invasiveness nature, OCT enables longitudinal imaging of developing specimens in vivo without potential damage from surgical operation, tissue fixation and processing, and staining with exogenous contrast agents. In this paper, various OCT applications in brain imaging and developmental biology are reviewed, with a particular focus on imaging heart development. In addition, we report findings on the effects of a circadian gene (Clock) and high-fat-diet on heart development in Drosophila melanogaster. These findings contribute to our understanding of the fundamental mechanisms connecting circadian genes and obesity to heart development and cardiac diseases.
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Affiliation(s)
- Jing Men
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
| | - Yongyang Huang
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
| | - Jitendra Solanki
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
| | - Xianxu Zeng
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
- Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China, 450000
| | - Aneesh Alex
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
| | - Jason Jerwick
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
| | - Zhan Zhang
- Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China, 450000
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA, 02129
| | - Airong Li
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA, 02129
| | - Chao Zhou
- Department of Electrical and Computer Engineering, Center for Photonics and Nanoelectronics, and Bioengineering Program, Lehigh University, Bethlehem, PA, USA, 18015
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17
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Viehland C, Keller B, Carrasco-Zevallos OM, Nankivil D, Shen L, Mangalesh S, Viet DT, Kuo AN, Toth CA, Izatt JA. Enhanced volumetric visualization for real time 4D intraoperative ophthalmic swept-source OCT. BIOMEDICAL OPTICS EXPRESS 2016; 7:1815-29. [PMID: 27231623 PMCID: PMC4871083 DOI: 10.1364/boe.7.001815] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 05/22/2023]
Abstract
Current-generation software for rendering volumetric OCT data sets based on ray casting results in volume visualizations with indistinct tissue features and sub-optimal depth perception. Recent developments in hand-held and microscope-integrated intrasurgical OCT designed for real-time volumetric imaging motivate development of rendering algorithms which are both visually appealing and fast enough to support real time rendering, potentially from multiple viewpoints for stereoscopic visualization. We report on an enhanced, real time, integrated volumetric rendering pipeline which incorporates high performance volumetric median and Gaussian filtering, boundary and feature enhancement, depth encoding, and lighting into a ray casting volume rendering model. We demonstrate this improved model implemented on graphics processing unit (GPU) hardware for real-time volumetric rendering of OCT data during tissue phantom and live human surgical imaging. We show that this rendering produces enhanced 3D visualizations of pathology and intraoperative maneuvers compared to standard ray casting.
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Affiliation(s)
- Christian Viehland
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Brenton Keller
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | - Derek Nankivil
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Liangbo Shen
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Shwetha Mangalesh
- Deparment of Ophthalmology, Duke University Medical Center, Durham NC 27710, USA
| | - Du Tran Viet
- Deparment of Ophthalmology, Duke University Medical Center, Durham NC 27710, USA
| | - Anthony N. Kuo
- Deparment of Ophthalmology, Duke University Medical Center, Durham NC 27710, USA
| | - Cynthia A. Toth
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Deparment of Ophthalmology, Duke University Medical Center, Durham NC 27710, USA
| | - Joseph A. Izatt
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Deparment of Ophthalmology, Duke University Medical Center, Durham NC 27710, USA
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18
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Wang T, Pfeiffer T, Regar E, Wieser W, van Beusekom H, Lancee CT, Springeling G, Krabbendam I, van der Steen AF, Huber R, van Soest G. Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2015; 6:5021-32. [PMID: 26713214 PMCID: PMC4679274 DOI: 10.1364/boe.6.005021] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/26/2015] [Accepted: 10/30/2015] [Indexed: 05/18/2023]
Abstract
Cardiac motion artifacts, non-uniform rotational distortion and undersampling affect the image quality and the diagnostic impact of intravascular optical coherence tomography (IV-OCT). In this study we demonstrate how these limitations of IV-OCT can be addressed by using an imaging system that we called "Heartbeat OCT", combining a fast Fourier Domain Mode Locked laser, fast pullback, and a micromotor actuated catheter, designed to examine a coronary vessel in less than one cardiac cycle. We acquired in vivo data sets of two coronary arteries in a porcine heart with both Heartbeat OCT, working at 2.88 MHz A-line rate, 4000 frames/s and 100 mm/s pullback speed, and with a commercial system. The in vivo results show that Heartbeat OCT provides faithfully rendered, motion-artifact free, fully sampled vessel wall architecture, unlike the conventional IV-OCT data. We present the Heartbeat OCT system in full technical detail and discuss the steps needed for clinical translation of the technology.
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Affiliation(s)
- Tianshi Wang
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
- These authors contributed equally to this work
| | - Tom Pfeiffer
- Lehrstuhl für Biomolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, München 80538,
Germany
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck
Germany
- These authors contributed equally to this work
| | - Evelyn Regar
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
| | - Wolfgang Wieser
- Lehrstuhl für Biomolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, München 80538,
Germany
| | - Heleen van Beusekom
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
| | - Charles T. Lancee
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
| | - Geert Springeling
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
| | - Ilona Krabbendam
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
| | - Antonius F.W. van der Steen
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 518055 Shenzhen,
China
- Department of Imaging science and Technology, Delft University of Technology, Postbus 5, Delft 2600 AA,
The Netherlands
| | - Robert Huber
- Lehrstuhl für Biomolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, München 80538,
Germany
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck
Germany
| | - Gijs van Soest
- Thorax Center, Erasmus University Medical Center, P. O. Box 2040, Rotterdam 3000 CA,
The Netherlands
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19
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Jirauschek C, Huber R. Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers. BIOMEDICAL OPTICS EXPRESS 2015; 6:2448-2465. [PMID: 26203373 PMCID: PMC4505701 DOI: 10.1364/boe.6.002448] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/10/2015] [Indexed: 05/18/2023]
Abstract
We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth.
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Affiliation(s)
- Christian Jirauschek
- Institute for Nanoelectronics, Technische Universität München, Arcisstr. 21, D-80333 Munich,
Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, D-23562 Lübeck,
Germany
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, D-80538 Munich,
Germany
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20
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Wei X, Xu J, Xu Y, Yu L, Xu J, Li B, Lau AKS, Wang X, Zhang C, Tsia KK, Wong KKY. Breathing laser as an inertia-free swept source for high-quality ultrafast optical bioimaging. OPTICS LETTERS 2014; 39:6593-6. [PMID: 25490629 DOI: 10.1364/ol.39.006593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We demonstrate an all-fiber breathing laser as inertia-free swept source (BLISS), with an ultra-compact design, for the emerging ultrafast bioimaging modalities. The unique feature of BLISS is its broadband wavelength-swept operation (∼60 nm) with superior temporal stability in terms of both long term (0.08 dB over 27 h) and shot-to-shot power variations (2.1%). More importantly, it enables a wavelength sweep rate of >10 MHz (∼7×10⁸ nm/s)—orders-of-magnitude faster than the existing swept sources based on mechanical or electrical tuning techniques. BLISS thus represents a practical and new generation of swept source operating in the unmet megahertz swept-rate regime that aligns with the pressing need for scaling the optical bioimaging speed in ultrafast phenomena study or high-throughput screening applications. To showcase its utility in high-speed optical bioimaging, we here employ BLISS for ultrafast time-stretch microscopy and multi-MHz optical coherence tomography of the biological specimen at a single-shot line-scan rate or A-scan rate of 11.5 MHz.
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21
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Wieser W, Draxinger W, Klein T, Karpf S, Pfeiffer T, Huber R. High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s. BIOMEDICAL OPTICS EXPRESS 2014; 5:2963-77. [PMID: 25401010 PMCID: PMC4230855 DOI: 10.1364/boe.5.002963] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 05/18/2023]
Abstract
We present a 1300 nm OCT system for volumetric real-time live OCT acquisition and visualization at 1 billion volume elements per second. All technological challenges and problems associated with such high scanning speed are discussed in detail as well as the solutions. In one configuration, the system acquires, processes and visualizes 26 volumes per second where each volume consists of 320 x 320 depth scans and each depth scan has 400 usable pixels. This is the fastest real-time OCT to date in terms of voxel rate. A 51 Hz volume rate is realized with half the frame number. In both configurations the speed can be sustained indefinitely. The OCT system uses a 1310 nm Fourier domain mode locked (FDML) laser operated at 3.2 MHz sweep rate. Data acquisition is performed with two dedicated digitizer cards, each running at 2.5 GS/s, hosted in a single desktop computer. Live real-time data processing and visualization are realized with custom developed software on an NVidia GTX 690 dual graphics processing unit (GPU) card. To evaluate potential future applications of such a system, we present volumetric videos captured at 26 and 51 Hz of planktonic crustaceans and skin.
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Affiliation(s)
- Wolfgang Wieser
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Wolfgang Draxinger
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Thomas Klein
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Sebastian Karpf
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Tom Pfeiffer
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Robert Huber
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck Germany
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22
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Cheng KHY, Mariampillai A, Lee KKC, Vuong B, Luk TWH, Ramjist J, Curtis A, Jakubovic H, Kertes P, Letarte M, Faughnan ME, HHT Investigator Group BVMC, Yang VXD. Histogram flow mapping with optical coherence tomography for in vivo skin angiography of hereditary hemorrhagic telangiectasia. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086015. [PMID: 25140883 PMCID: PMC4407667 DOI: 10.1117/1.jbo.19.8.086015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/09/2014] [Accepted: 07/21/2014] [Indexed: 05/24/2023]
Abstract
Speckle statistics of flowing scatterers have been well documented in the literature. Speckle variance optical coherence tomography exploits the large variance values of intensity changes in time caused mainly by the random backscattering of light resulting from translational activity of red blood cells to map out the microvascular networks. A method to map out the microvasculature malformation of skin based on the time-domain histograms of individual pixels is presented with results obtained from both normal skin and skin containing vascular malformation. Results demonstrated that this method can potentially map out deeper blood vessels and enhance the visualization of microvasculature in low signal regions, while being resistant against motion (e.g., patient tremor or internal reflex movements). The overall results are manifested as more uniform en face projection maps of microvessels. Potential applications include clinical imaging of skin vascular abnormalities and wide-field skin angiography for the study of complex vascular networks.
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Affiliation(s)
- Kyle H. Y. Cheng
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto M5S 3G4, Canada
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
| | - Adrian Mariampillai
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
- Ryerson University, Department of Electrical and Computer Engineering, Toronto M5B 2K3, Canada
| | - Kenneth K. C. Lee
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto M5S 3G4, Canada
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
| | - Barry Vuong
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
- Ryerson University, Department of Electrical and Computer Engineering, Toronto M5B 2K3, Canada
| | - Timothy W. H. Luk
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
- Ryerson University, Department of Electrical and Computer Engineering, Toronto M5B 2K3, Canada
| | - Joel Ramjist
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
| | - Anne Curtis
- University of Toronto, Department of Medicine, Toronto M5S 1A8, Canada
| | - Henry Jakubovic
- University of Toronto, St. Michael’s Hospital, Dermatopathology, Department of Laboratory Medicine, Toronto M5B 1W8, Canada
| | - Peter Kertes
- University of Toronto, John and Liz Tory Eye Centre, Sunnybrook Health Sciences Centre, Department of Ophthalmology and Vision Sciences, Toronto M4N 3M5, Canada
| | - Michelle Letarte
- SickKids Research Institute, Hospital for Sick Children, Toronto M5G 1X8, Canada
- University of Toronto, Department of Immunology, Toronto M5S 1A8, Canada
| | - Marie E. Faughnan
- University of Toronto, St. Michael’s Hospital, Toronto HHT Program, Division of Respirology, Department of Medicine, Toronto M5B 1W8, Canada
- St. Michaels Hospital, Li Ka Shing Knowledge Institute, Toronto M5B 1W8, Canada
| | | | - Victor X. D. Yang
- Ryerson University, Biophotonics and Bioengineering Laboratory, Toronto M5B 2K3, Canada
- Ryerson University, Department of Electrical and Computer Engineering, Toronto M5B 2K3, Canada
- Sunnybrook Health Science Centre, Division of Neurosurgery, Toronto M4N 3M5, Canada
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23
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Rohde F, Benkler E, Puppe T, Unterreitmayer R, Zach A, Telle HR. Phase-predictable tuning of single-frequency optical synthesizers. OPTICS LETTERS 2014; 39:4080-4083. [PMID: 25121656 DOI: 10.1364/ol.39.004080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigate the tuning behavior of a novel type of single-frequency optical synthesizers by phase comparison of the output signals of two identical devices. We achieve phase-stable and cycle-slip free frequency tuning over 28.1 GHz with a maximum zero-to-peak phase deviation of 62 mrad. In contrast to previous implementations of single-frequency optical synthesizers, no comb line order switching is needed when tuned over more than one comb line spacing range of the employed frequency comb.
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24
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Rüegsegger MB, Geiser D, Steiner P, Pica A, Aebersold DM, Kowal JH. Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept. Med Phys 2014; 41:081704. [DOI: 10.1118/1.4885975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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25
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Abstract
The technical progress of the recent years has revolutionized imaging in ophthalmology. Scanning laser ophthalmoscopy (SLO), digital angiography, optical coherence tomography (OCT), and detection of fundus autofluorescence (FAF) have fundamentally changed our understanding of numerous retinal and choroidal diseases. Besides the tremendous advances in macular diagnostics, there is more and more evidence that central pathologies are often directly linked to changes in the peripheral retina. This review provides a brief overview on current posterior segment imaging techniques with a special focus on the peripheral retina.
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Affiliation(s)
- Marcus Kernt
- Department of Ophthalmology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Anselm Kampik
- Department of Ophthalmology, Ludwig-Maximilians-University of Munich, Munich, Germany
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26
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Li P, Johnstone M, Wang RK. Full anterior segment biometry with extended imaging range spectral domain optical coherence tomography at 1340 nm. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:046013. [PMID: 24752381 PMCID: PMC3993014 DOI: 10.1117/1.jbo.19.4.046013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/24/2014] [Indexed: 05/11/2023]
Abstract
We demonstrate an extended-imaging-range anterior-segment optical coherence tomography (eAS-OCT) system for the biometric assessment of full AS in human eye. This newly developed eAS-OCT operating at 1340-nm wavelength band is simultaneously capable of an imaging speed of 120 kHz A-line scan rate, an axial resolution of 7.2 μm, and an extended imaging range of up to 16 mm in air. Imaging results from three healthy subjects and one subject with a narrow-angle demonstrate the instrument's utility. With this system, it can provide anatomical dimensions of AS, including central corneal thickness, anterior chamber width, anterior chamber depth, crystalline lens vault, crystalline lens thickness, angle opening distance (AOD500/AOD750), and the area described by the trabecular-iris space (TISA500/TISA750) at 500/750 μm. We also use eAS-OCT to image and quantify dynamic functional changes of the AS in response to a light stimulus that induces physiological pupillary changes as well as accommodative efforts that induce lens changes. The results show that the described eAS-OCT is able to provide full anatomical biometry for AS and is useful for the studies where the dynamic response of AS compartment to certain stimulus is required.
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Affiliation(s)
- Peng Li
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
| | - Murray Johnstone
- University of Washington, Department of Ophthalmology, Seattle, Washington 98104
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
- University of Washington, Department of Ophthalmology, Seattle, Washington 98104
- Address all correspondence to: Ruikang K. Wang, E-mail:
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27
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Zhou C, Alex A, Rasakanthan J, Ma Y. Space-division multiplexing optical coherence tomography. OPTICS EXPRESS 2013; 21:19219-27. [PMID: 23938839 PMCID: PMC3756223 DOI: 10.1364/oe.21.019219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/15/2013] [Accepted: 07/31/2013] [Indexed: 05/17/2023]
Abstract
High speed, high resolution and high sensitivity are desirable for optical coherence tomography (OCT). Here, we demonstrate a space-division multiplexing (SDM) technology that translates long coherence length of a commercially available wavelength tunable laser into high OCT imaging speed. We achieved an effective 800,000 A-scans/s imaging speed using a 100,000 Hz tunable vertical cavity surface-emitting laser (VCSEL). A sensitivity of 94.6 dB and a roll-off of < 2 dB over ~30 mm imaging depth were measured from a single channel in the prototype SDM-OCT system. An axial resolution of ~11 μm in air (or ~8.3 μm in tissue) was achieved throughout the entire depth range. An in vivo, 3D SDM-OCT volume of an entire Drosophila larva consisting of 400 x 605 A-scans was acquired in 0.37 seconds. Synchronized cross-sectional OCT imaging of three different segments of a beating Drosophila larva heart is demonstrated. The SDM technology provides a new orthogonal dimension for further speed improvement for OCT with favorable cost scaling. SDM-OCT also preserves image resolution and allows synchronized cross-sectional and three-dimensional (3D) imaging of biological samples, enabling new biomedical applications.
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Affiliation(s)
- Chao Zhou
- Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
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Slepneva S, Kelleher B, O'Shaughnessy B, Hegarty SP, Vladimirov AG, Huyet G. Dynamics of Fourier domain mode-locked lasers. OPTICS EXPRESS 2013; 21:19240-51. [PMID: 23938841 DOI: 10.1364/oe.21.019240] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
An analysis of the dynamical features in the output of a Fourier Domain Mode Locked laser is presented. An experimental study of the wavelength sweep-direction asymmetry in the output of such devices is undertaken. A mathematical model based on a set of delay differential equations is developed and shown to agree well with experiment.
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Affiliation(s)
- S Slepneva
- Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork, Ireland
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29
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Zurauskas M, Bradu A, Podoleanu AG. Frequency multiplexed long range swept source optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2013; 4:778-88. [PMID: 23760762 PMCID: PMC3675859 DOI: 10.1364/boe.4.000778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/30/2013] [Accepted: 04/30/2013] [Indexed: 05/13/2023]
Abstract
We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample.
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30
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Wang T, Wieser W, Springeling G, Beurskens R, Lancee CT, Pfeiffer T, van der Steen AFW, Huber R, van Soest G. Intravascular optical coherence tomography imaging at 3200 frames per second. OPTICS LETTERS 2013; 38:1715-7. [PMID: 23938921 DOI: 10.1364/ol.38.001715] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate intravascular optical coherence tomography (OCT) imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous motor. The OCT system, with an imaging depth of 3.7 mm (in air), is based on a Fourier domain mode locked laser operating at an A-line rate of 1.6 MHz. The diameter of the catheter is 1.1 mm at the tip. Ex vivo images of human coronary artery (78.4 mm length) were acquired at a pullback speed of 100 mm/s. True 3D volumetric imaging of the entire artery, with dense and isotropic sampling in all dimensions, was performed in <1 second acquisition time.
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Affiliation(s)
- Tianshi Wang
- Thorax Center, Erasmus University Medical Center, Rotterdam, The Netherlands.
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31
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Klein T, Wieser W, Reznicek L, Neubauer A, Kampik A, Huber R. Multi-MHz retinal OCT. BIOMEDICAL OPTICS EXPRESS 2013; 4:1890-908. [PMID: 24156052 PMCID: PMC3799654 DOI: 10.1364/boe.4.001890] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 05/17/2023]
Abstract
We analyze the benefits and problems of in vivo optical coherence tomography (OCT) imaging of the human retina at A-scan rates in excess of 1 MHz, using a 1050 nm Fourier-domain mode-locked (FDML) laser. Different scanning strategies enabled by MHz OCT line rates are investigated, and a simple multi-volume data processing approach is presented. In-vivo OCT of the human ocular fundus is performed at different axial scan rates of up to 6.7 MHz. High quality non-mydriatic retinal imaging over an ultra-wide field is achieved by a combination of several key improvements compared to previous setups. For the FDML laser, long coherence lengths and 72 nm wavelength tuning range are achieved using a chirped fiber Bragg grating in a laser cavity at 419.1 kHz fundamental tuning rate. Very large data sets can be acquired with sustained data transfer from the data acquisition card to host computer memory, enabling high-quality averaging of many frames and of multiple aligned data sets. Three imaging modes are investigated: Alignment and averaging of 24 data sets at 1.68 MHz axial line rate, ultra-dense transverse sampling at 3.35 MHz line rate, and dual-beam imaging with two laser spots on the retina at an effective line rate of 6.7 MHz.
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Affiliation(s)
- Thomas Klein
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Wolfgang Wieser
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Lukas Reznicek
- Augenklinik der Ludwig-Maximilians-Universität München, Mathildenstraße 8, 80336 Munich, Germany
| | - Aljoscha Neubauer
- Augenklinik der Ludwig-Maximilians-Universität München, Mathildenstraße 8, 80336 Munich, Germany
| | - Anselm Kampik
- Augenklinik der Ludwig-Maximilians-Universität München, Mathildenstraße 8, 80336 Munich, Germany
| | - Robert Huber
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
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