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Gupta P, Vairagi K, Sharma V, Prasad KK, Mondal SK. Tissue characterization using axicon probe-assisted common-path optical coherence tomography. OPTICS EXPRESS 2024; 32:20194-20206. [PMID: 38859135 DOI: 10.1364/oe.508006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/03/2024] [Indexed: 06/12/2024]
Abstract
In this work, a common-path optical coherence tomography (OCT) system is demonstrated for characterizing the tissue in terms of some optical properties. A negative axicon structure chemically etched inside the fiber tip is employed as optical probe in the OCT. This probe generates a quality Bessel beam owning a large depth-of-field, ∼700 µm and small central spot size, ∼3 µm. The OCT system is probing the sample without using any microscopic lens. For experimental validation, the OCT imaging of chicken tissue has been obtained along with estimation of its refractive index and optical attenuation coefficient. Afterwards, the cancerous tissue is differentiated from the normal tissue based on the OCT imaging, refractive index, and optical attenuation coefficient. The respective tissue samples are collected from the human liver and pancreas. This probe could be a useful tool for endoscopic or minimal-invasive inspection of malignancy inside the tissue either at early-stage or during surgery.
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Lee Y, Low MJ, Yang D, Nam HK, Le TSD, Lee SE, Han H, Kim S, Vu QH, Yoo H, Yoon H, Lee J, Sandeep S, Lee K, Kim SW, Kim YJ. Ultra-thin light-weight laser-induced-graphene (LIG) diffractive optics. LIGHT, SCIENCE & APPLICATIONS 2023; 12:146. [PMID: 37322023 DOI: 10.1038/s41377-023-01143-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/13/2023] [Accepted: 03/30/2023] [Indexed: 06/17/2023]
Abstract
The realization of hybrid optics could be one of the best ways to fulfill the technological requirements of compact, light-weight, and multi-functional optical systems for modern industries. Planar diffractive lens (PDL) such as diffractive lenses, photonsieves, and metasurfaces can be patterned on ultra-thin flexible and stretchable substrates and be conformally attached on top of arbitrarily shaped surfaces. In this review, we introduce recent research works addressed to the design and manufacturing of ultra-thin graphene optics, which will open new markets in compact and light-weight optics for next-generation endoscopic brain imaging, space internet, real-time surface profilometry, and multi-functional mobile phones. To provide higher design flexibility, lower process complexity, and chemical-free process with reasonable investment cost, direct laser writing (DLW) of laser-induced-graphene (LIG) is actively being applied to the patterning of PDL. For realizing the best optical performances in DLW, photon-material interactions have been studied in detail with respect to different laser parameters; the resulting optical characteristics have been evaluated in terms of amplitude and phase. A series of exemplary laser-written 1D and 2D PDL structures have been actively demonstrated with different base materials, and then, the cases are being expanded to plasmonic and holographic structures. The combination of these ultra-thin and light-weight PDL with conventional bulk refractive or reflective optical elements could bring together the advantages of each optical element. By integrating these suggestions, we suggest a way to realize the hybrid PDL to be used in the future micro-electronics surface inspection, biomedical, outer space, and extended reality (XR) industries.
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Affiliation(s)
- Younggeun Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Mun Ji Low
- School of Mechanical and Aerospace Engineering, Nanyang Technological University (NTU), 50 Nanyang Avenue, 639798, Singapore, Singapore
- Panasonic Factory Solutions Asia Pacific (PFSAP), 285 Jalan Ahmad Ibrahim, 639931, Singapore, Singapore
| | - Dongwook Yang
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Han Ku Nam
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Truong-Son Dinh Le
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seung Eon Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyogeun Han
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seunghwan Kim
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Quang Huy Vu
- Department of Mechanical System Design Engineering, Seoul National University of Science and Technology (Seuoltech), 232 Gongneung-ro, Nowon-gu, Seoul, 01811, Republic of Korea
| | - Hongki Yoo
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyosang Yoon
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Joohyung Lee
- Department of Mechanical System Design Engineering, Seoul National University of Science and Technology (Seuoltech), 232 Gongneung-ro, Nowon-gu, Seoul, 01811, Republic of Korea
| | - Suchand Sandeep
- School of Mechanical and Aerospace Engineering, Nanyang Technological University (NTU), 50 Nanyang Avenue, 639798, Singapore, Singapore
| | - Keunwoo Lee
- LASER N GRAPN INC., 193 Munji-ro, Yuseong-gu, Daejeon, 34051, Republic of Korea
| | - Seung-Woo Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Young-Jin Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
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Vairagi K, Gupta P, Tiwari UK, Mondal SK. Reflective axicon based energy-efficient extended depth of focus quasi-Bessel beam probe for common-path optical coherence tomography. APPLIED OPTICS 2023; 62:511-517. [PMID: 36821252 DOI: 10.1364/ao.465544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/30/2022] [Indexed: 06/18/2023]
Abstract
This work presents an optical fiber negative/reflective axicon probe that generates an energy-efficient quasi-Bessel beam (QBB) having a central spot (CS) possessing ∼20% of the QBB power. With silver coating around the axicon, the CS power has been increased by ∼45%. The QBB possesses a large depth of field, ∼400µm, with a micron order spot size as obtained experimentally. The probe has further been explored for common-path optical coherence tomography. The probe length has been optimized to minimize the path length difference between the reference and sample signal. With a divergence angle of just 0.013°, the beam provides a lateral resolution of ∼2.5 to ∼16µm for an axial distance of 0.1 to 1.0 mm. The imaging results are presented for standard samples such as onion and Scotch tape.
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Pragmatic Micrometre to Millimetre Calibration Using Multiple Methods for Low-Coherence Interferometer in Embedded Metrology Applications. SENSORS 2021; 21:s21155101. [PMID: 34372336 PMCID: PMC8347976 DOI: 10.3390/s21155101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 11/16/2022]
Abstract
In-situ metrology utilised for surface topography, texture and form analysis along with quality control processes requires a high-level of reliability. Hence, a traceable method for calibrating the measurement system's transfer function is required at regular intervals. This paper compares three methods of dimensional calibration for a spectral domain low coherence interferometer using a reference laser interferometer versus two types of single material measure. Additionally, the impact of dataset sparsity is shown along with the effect of using a singular calibration dataset for system performance when operating across different media.
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Comparison of Pulse Wave Signal Monitoring Techniques with Different Fiber-Optic Interferometric Sensing Elements. PHOTONICS 2021. [DOI: 10.3390/photonics8050142] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Pulse wave (PW) measurement is a highly prominent technique, used in biomedical diagnostics. Development of novel PW sensors with increased accuracy and reduced susceptibility to motion artifacts will pave the way to more advanced healthcare technologies. This paper reports on a comparison of performance of fiber optic pulse wave sensors, based on Fabry–Perot interferometer, fiber Bragg grating, optical coherence tomography (OCT) and singlemode-multimode-singlemode intermodal interferometer. Their performance was tested in terms of signal to noise ratio, repeatability of demodulated signals and suitability of demodulated signals for extraction of information about direct and reflected waves. It was revealed that the OCT approach of PW monitoring provided the best demodulated signal quality and was most robust against motion artifacts. Advantages and drawbacks of all compared PW measurement approaches in terms of practical questions, such as multiplexing capabilities and abilities to be interrogated by portable hardware are discussed.
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Qiu J, Meng J, Liu Z, Han T, Ding Z. Fast simulation and design of the fiber probe with a fiber-based pupil filter for optical coherence tomography using the eigenmode expansion approach. OPTICS EXPRESS 2021; 29:2172-2183. [PMID: 33726418 DOI: 10.1364/oe.416279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Fiber probes for optical coherence tomography (OCT) recently employ a short section of step-index multimode fiber (SIMMF) to generate output beams with extended depth of focus (DOF). As the focusing region of the output beam is generally close to the probe end, it is not feasible to adopt the methods for bulk-optics with spatial pupil filters to the fiber probes with fiber-based filters. On the other hand, the applicable method of the beam propagation method (BPM) to the fiber probes is computationally inefficient to perform parameter scan and exhaustive search optimization. In this paper, we propose the method which analyzes the non-Gaussian beams from the fiber probes with fiber-based filters using the eigenmode expansion (EME) method. Furthermore, we confirm the power of this method in designing fiber-based filters with increased DOF gain and uniformly focusing by introducing more and higher-order fiber modes. These results using the EME method are in good agreement with that by the BPM, while the latter takes 1-2 orders more computation time. With higher-order fiber modes involved, a novel probe design with increased DOF gain and suppressed sidelobe is proposed. Our findings reveal that the fiber probes based on SIMMFs are able to achieve about four times DOF gain at maximum with uniformly focusing under acceptable modal dispersion. The EME method enables fast and accurate simulation of fiber probes based on SIMMFs, which is important in the design of high-performance fiber-based micro-imaging systems for biomedical applications.
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Bessel Beam: Significance and Applications-A Progressive Review. MICROMACHINES 2020; 11:mi11110997. [PMID: 33187147 PMCID: PMC7697033 DOI: 10.3390/mi11110997] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/07/2020] [Accepted: 11/09/2020] [Indexed: 01/13/2023]
Abstract
Diffraction is a phenomenon related to the wave nature of light and arises when a propagating wave comes across an obstacle. Consequently, the wave can be transformed in amplitude or phase and diffraction occurs. Those parts of the wavefront avoiding an obstacle form a diffraction pattern after interfering with each other. In this review paper, we have discussed the topic of non-diffractive beams, explicitly Bessel beams. Such beams provide some resistance to diffraction and hence are hypothetically a phenomenal alternate to Gaussian beams in several circumstances. Several outstanding applications are coined to Bessel beams and have been employed in commercial applications. We have discussed several hot applications based on these magnificent beams such as optical trapping, material processing, free-space long-distance self-healing beams, optical coherence tomography, superresolution, sharp focusing, polarization transformation, increased depth of focus, birefringence detection based on astigmatic transformed BB and encryption in optical communication. According to our knowledge, each topic presented in this review is justifiably explained.
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Li J, Thiele S, Quirk BC, Kirk RW, Verjans JW, Akers E, Bursill CA, Nicholls SJ, Herkommer AM, Giessen H, McLaughlin RA. Ultrathin monolithic 3D printed optical coherence tomography endoscopy for preclinical and clinical use. LIGHT, SCIENCE & APPLICATIONS 2020; 9:124. [PMID: 32704357 PMCID: PMC7371638 DOI: 10.1038/s41377-020-00365-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 06/23/2020] [Accepted: 07/04/2020] [Indexed: 05/03/2023]
Abstract
Preclinical and clinical diagnostics increasingly rely on techniques to visualize internal organs at high resolution via endoscopes. Miniaturized endoscopic probes are necessary for imaging small luminal or delicate organs without causing trauma to tissue. However, current fabrication methods limit the imaging performance of highly miniaturized probes, restricting their widespread application. To overcome this limitation, we developed a novel ultrathin probe fabrication technique that utilizes 3D microprinting to reliably create side-facing freeform micro-optics (<130 µm diameter) on single-mode fibers. Using this technique, we built a fully functional ultrathin aberration-corrected optical coherence tomography probe. This is the smallest freeform 3D imaging probe yet reported, with a diameter of 0.457 mm, including the catheter sheath. We demonstrated image quality and mechanical flexibility by imaging atherosclerotic human and mouse arteries. The ability to provide microstructural information with the smallest optical coherence tomography catheter opens a gateway for novel minimally invasive applications in disease.
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Affiliation(s)
- Jiawen Li
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Simon Thiele
- Institute of Applied Optics (ITO) and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
| | - Bryden C. Quirk
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Rodney W. Kirk
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Johan W. Verjans
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA 5000 Australia
- Royal Adelaide Hospital, Adelaide, SA 5000 Australia
| | - Emma Akers
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA 5000 Australia
| | - Christina A. Bursill
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA 5000 Australia
| | - Stephen J. Nicholls
- Monash Cardiovascular Research Centre, Monash University, Melbourne, VIC 3168 Australia
| | - Alois M. Herkommer
- Institute of Applied Optics (ITO) and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
| | - Harald Giessen
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
| | - Robert A. McLaughlin
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide Medical School, University of Adelaide, Adelaide, SA 5005 Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia
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Li Y, Moon S, Chen JJ, Zhu Z, Chen Z. Ultrahigh-sensitive optical coherence elastography. LIGHT, SCIENCE & APPLICATIONS 2020; 9:58. [PMID: 32337022 PMCID: PMC7154028 DOI: 10.1038/s41377-020-0297-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 05/07/2023]
Abstract
The phase stability of an optical coherence elastography (OCE) system is the key determining factor for achieving a precise elasticity measurement, and it can be affected by the signal-to-noise ratio (SNR), timing jitters in the signal acquisition process, and fluctuations in the optical path difference (OPD) between the sample and reference arms. In this study, we developed an OCE system based on swept-source optical coherence tomography (SS-OCT) with a common-path configuration (SS-OCECP). Our system has a phase stability of 4.2 mrad without external stabilization or extensive post-processing, such as averaging. This phase stability allows us to detect a displacement as small as ~300 pm. A common-path interferometer was incorporated by integrating a 3-mm wedged window into the SS-OCT system to provide intrinsic compensation for polarization and dispersion mismatch, as well as to minimize phase fluctuations caused by the OPD variation. The wedged window generates two reference signals that produce two OCT images, allowing for averaging to improve the SNR. Furthermore, the electrical components are optimized to minimize the timing jitters and prevent edge collisions by adjusting the delays between the trigger, k-clock, and signal, utilizing a high-speed waveform digitizer, and incorporating a high-bandwidth balanced photodetector. We validated the SS-OCECP performance in a tissue-mimicking phantom and an in vivo rabbit model, and the results demonstrated a significantly improved phase stability compared to that of the conventional SS-OCE. To the best of our knowledge, we demonstrated the first SS-OCECP system, which possesses high-phase stability and can be utilized to significantly improve the sensitivity of elastography.
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Affiliation(s)
- Yan Li
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92612 USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617 USA
| | - Sucbei Moon
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92612 USA
- Department of Physics, Kookmin University, Seoul, 02707 South Korea
| | - Jason J. Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92612 USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617 USA
| | - Zhikai Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92612 USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617 USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92612 USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617 USA
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Qiu J, Han T, Liu Z, Meng J, Ding Z. Uniform focusing with an extended depth range and increased working distance for optical coherence tomography by an ultrathin monolith fiber probe. OPTICS LETTERS 2020; 45:976-979. [PMID: 32058521 DOI: 10.1364/ol.383428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
It is difficult to maintain high transverse resolution over an increased depth range using miniature probes for optical coherence tomography (OCT) due to the rapid divergence of light and the space limitation. To solve this problem, we introduce a fiber-based filter in the proposed probe to manipulate its output beam. Significant mode interference (MI) is exploited to enhance the depth of focus (DOF), and the mode phase difference is tuned to achieve a uniform axial intensity within the DOF. The magnified MI field instead of the diffracted one is adopted as the final pupil filter in the probe to increase its working distance (WD). The probe is fabricated with a diameter of 125 µm and a total length of 2.6 mm for its distal fiber optics. Compared to the conventional probe with similar minimal lateral resolution of better than 4.4 µm, the proposed probe achieves two times that of the DOF gain and 1.7 times that of the WD. Improvements in performance of the probe are demonstrated by OCT imaging using a fresh lemon and human skin. With merits of enhanced imaging quality and easy fabrication, the proposed probe poses great potential for important applications, especially for endoscopic imaging of human internal organs in vivo.
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Wang C, Zhang Q, Wang Y, Zhang X, Zhang L. Long-range common-path spectral domain optical coherence tomography. OPTICS EXPRESS 2019; 27:12483-12490. [PMID: 31052787 DOI: 10.1364/oe.27.012483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Fiber-based common-path spectral domain optical coherence tomography (SD-OCT) is compact and polarization insensitive, which is usually used in endoscopic biomedical imaging. In this study, we investigate a method to extend the working distance of a common-path SD-OCT system. Common-path OCT light, which consisting of sample and reference light signal, is directed into a free space optical interferometer. The OCT light is split spatially into two beam segments by a wavefront-splitting mirror, and the two parallel beams interfere noncollinearly in the interferometer. Distance between the end of the probing fiber, which serves as the reference plane of our OCT system, and the OCT sample is about 140 mm. The OCT performance is demonstrated by imaging biological samples. The proposed method can be used to develop polarization insensitive OCT probe for biomedical imaging applications.
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Wang W, Wang G, Ma J, Cheng L, Guan BO. Miniature all-fiber axicon probe with extended Bessel focus for optical coherence tomography. OPTICS EXPRESS 2019; 27:358-366. [PMID: 30696123 DOI: 10.1364/oe.27.000358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
The trade-off between lateral resolution and depth of focus (DOF) severely limits the capability of endoscopic optical coherence tomography (OCT) for high-resolution deep-tissue imaging. To address this issue, we developed a novel miniature all-fiber axicon OCT probe by inserting a segment of gradient-index (GRIN) fiber between a piece of single-mode fiber (SMF) and an axicon polished from a no-core fiber. The GRIN lens served as a beam expander extending the probe DOF by 5.2 times while maintaining a high lateral resolution of 2 μm. The DOF extension was experimentally verified by measuring the axial profile of the probe output beam and further by imaging multilayered polymer tapes and onion samples. The designed probe with a tight focus over a large DOF holds great potential in endoscopic OCT imaging of deep tissues at the cellular level.
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Marrese M, Offerhaus H, Paardekam E, Iannuzzi D. 70 μm diameter optical probe for common-path optical coherence tomography in air and liquids. OPTICS LETTERS 2018; 43:5929-5932. [PMID: 30547972 DOI: 10.1364/ol.43.005929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
We investigate and validate a novel method to fabricate ultrathin optical probes for common-path optical coherence tomography (CP-OCT). The probes are obtained using a 65 μm barium titanate microsphere inserted into an inward concave cone chemically etched at the end of a single-mode fiber. We demonstrate that the high refractive index (n=1.95) of the barium titanate microspheres allows one to maintain high sensitivity even while imaging in liquids, reaching a sensitivity of 83 dB. Due to its low cost, flexibility, and ease of use, the probe holds promise for the development of a new generation of ultrathin needle-based OCT systems.
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Yin B, Hyun C, Gardecki JA, Tearney GJ. Extended depth of focus for coherence-based cellular imaging. OPTICA 2017; 4:959-965. [PMID: 29675447 PMCID: PMC5902383 DOI: 10.1364/optica.4.000959] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Improving lateral resolution for cross-sectional optical coherence tomography (OCT) imaging is difficult due to the rapid divergence of light once it is focused to a small spot. To overcome this obstacle, we introduce a fiber optics system that generates a coaxially focused multimode (CAFM) beam for depth of focus (DOF) extension. We fabricated a CAFM beam OCT probe and show that the DOF is more than fivefold that of a conventional Gaussian beam, enabling cross-sectional imaging of biological tissues with clearly resolved cellular and subcellular structures over more than a 400 μm depth range. The compact and straightforward design and high-resolution extended DOF imaging capabilities of this technique suggests that it will be very useful for endoscopic cross-sectional imaging of human internal organs in vivo.
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Affiliation(s)
- Biwei Yin
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA
| | - Chulho Hyun
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA
| | - Joseph A. Gardecki
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- Department of Pathology, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA
- Corresponding author:
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Kim JB, Jeong KH. Batch fabrication of functional optical elements on a fiber facet using DMD based maskless lithography. OPTICS EXPRESS 2017; 25:16854-16859. [PMID: 28789184 DOI: 10.1364/oe.25.016854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 06/30/2017] [Indexed: 06/07/2023]
Abstract
We report a facile and direct fabrication method for integrating functional optical microstructures on the top surface of an optical fiber. A programmable maskless fabrication system was developed by using digital micromirror device (DMD), which allows rapid prototyping and low-cost fabrication without physical photomask. This maskless UV exposure system has the spatial resolution of 2.2 μm for an exposed area of 245 μm x 185 μm. Diverse optical microstructures were photolithographically defined on multimode fibers and a single mode optical fiber serially spliced with a coreless silica fiber segment. This method provides a new route for developing compact functional fiber-optic applications such as laser scanning, biosensing, or laser endomicroscopy.
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16
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Optical Coherence Microscopy. Methods Mol Biol 2017. [PMID: 28324609 DOI: 10.1007/978-1-4939-6810-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The present chapter aims at demonstrating the capabilities of optical coherence microscopy (OCM) for applications in biomedical imaging. We furthermore review the functional imaging capabilities of OCM focusing on lable-free optical angiography. We conclude with a section on digital wavefront control and a short outlook on future developments, in particular for contrast enhancement techniques.
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Cheon GW, Gehlbach PL, Kang JU. Ghost reduction in CP-SSOCT having multiple references using Fourier-domain Shift and Sum. IEEE PHOTONICS TECHNOLOGY LETTERS : A PUBLICATION OF THE IEEE LASER AND ELECTRO-OPTICS SOCIETY 2016; 28:1972-1975. [PMID: 28042225 PMCID: PMC5193392 DOI: 10.1109/lpt.2016.2580588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We propose, test and validate a novel Fourier-domain based method for ghost image artifacts reduction in a common-path SSOCT system having multiple adjacent reference planes. Common-path probes with imaging systems containing high-index sapphire ball or other lenses produce multiple fixed references due to Fresnel reflections from the lens surfaces. The multiple reference planes produce multiple and overlapping OCT images. Since such ghost artifacts are the result of the superposition of multiple identical images having different amplitudes and spatial shifts, one can correctly shift and sum the images in the Fourier-domain once the relative amplitude and lateral position between the reference planes are known. This theory and numerical testing are presented to elucidate our method. We then validate the potential effectiveness using OCT imaging experiments.
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Affiliation(s)
- Gyeong Woo Cheon
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peter L Gehlbach
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jin U Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
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18
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Ji CK, Feng YH, Sun LP, Gao S, Wan MG, Li J, Guan BO. Micrometer-resolution in-fiber OCT probe with tunable working distance. OPTICS EXPRESS 2016; 24:19814-19823. [PMID: 27557257 DOI: 10.1364/oe.24.019814] [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
Optical coherence tomography (OCT) is an attractive modality in biomedical imaging systems due to its non-invasive imaging character. Since the image quality of OCT may be limited by the decrease of transverse resolution away from the focus spot, working distance tunable probe can be a strategy to overcome such limitation and maintain high transverse resolution at different imaging depths. In this paper, a miniature, working distance-tunable in-fiber OCT probe is demonstrated. The influences of the graded index fiber (GIF) length as well as the air cavity length on the working distance and the transverse resolution are simulated and discussed. Experimental results prove that the working distance can be tuned freely from 337.31 μm to 22.28 μm, producing the transverse resolution from 13.86 μm to 3.6 μm, which are in good agreement with the simulated results. The application of the probe in an OCT system for imagining a standard USAF resolution target is investigated in detail. The best resolutions for the standard USAF resolution target imaging are 4.9 μm and 6.9 μm in horizontal and vertical direction, respectively.
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19
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Yin B, Chu KK, Liang CP, Singh K, Reddy R, Tearney GJ. μOCT imaging using depth of focus extension by self-imaging wavefront division in a common-path fiber optic probe. OPTICS EXPRESS 2016; 24:5555-5564. [PMID: 29092377 PMCID: PMC5499634 DOI: 10.1364/oe.24.005555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 05/06/2023]
Abstract
Optical coherence tomography (OCT) is an attractive medical modality due to its ability to acquire high-resolution, cross-sectional images inside the body using flexible, small-diameter, scanning fiber optic probes. Conventional, cross-sectional OCT imaging technologies have approximately 10-μm axial resolution and 30-μm lateral resolution, specifications that enable the visualization of microscopic architectural morphology. While this resolution is useful for many clinical applications, it is insufficient for resolving individual cells that characterize many diseases. To address this gap, a supercontinuum-laser-based, μm-resolution OCT (μOCT) system and a 500 μm-diameter, extended depth of focus single fiber optic probe for endoscopic and intravascular imaging were designed and fabricated. At the distal tip of the fiber optic probe, a cylindrical waveguide was used to divide the wavefront to provide multiple circular propagation modes. Once transmitted through a relatively high NA lens (NA >0.1), these modes were projected as multiple coaxial foci (~3 μm full width at half maximum (FWHM)) over a greatly extended focal depth range. The distal tip of the probe also contained a common-path reference reflectance to minimize polarization and dispersion imbalances between sample and reference arm light. Measurements showed that the probe provides a 20-fold depth of focus extension, maintaining a 3-5 µm lateral resolution (FWHM of PSF) and a 2 μm axial resolution over a depth range of approximately 1 mm. These results suggest that this new optical configuration will be useful for achieving high-resolution, cross-sectional OCT imaging in catheter/endoscope-based medical imaging devices.
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Affiliation(s)
- Biwei Yin
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Kengyeh K. Chu
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Chia-Pin Liang
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Kanwarpal Singh
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Rohith Reddy
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Department of Pathology, Harvard Medical School and Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
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20
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Lee SH, Ryu YT, Son DH, Jeong S, Kim Y, Ju S, Kim BH, Han WT. Radial-firing optical fiber tip containing conical-shaped air-pocket for biomedical applications. OPTICS EXPRESS 2015; 23:21254-21263. [PMID: 26367974 DOI: 10.1364/oe.23.021254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report a novel radial-firing optical fiber tip containing a conical-shaped air-pocket fabricated by deforming a hollow optical fiber using electric arc-discharge process. The hollow optical fiber was fusion spliced with a conventional optical fiber, simultaneously deforming into the intagliated conical-shaped region along the longitudinal fiber-axis of the fiber due to the gradual collapse of the cavity of the hollow optical fiber. Then the distal-end of the hollow optical fiber was sealed by the additional arc-discharge in order to obstruct the inflow of an external bio-substance or liquid to the inner air surface during the surgical operations, resulting in the formation of encased air-pocket in the silica glass fiber. Due to the total internal reflection of the laser beam at the conical-shaped air surface, the laser beam (λ = 632.8 nm) was deflected to the circumferential direction up to 87 degree with respect to the fiber-axis.
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21
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Montonen R, Kassamakov I, Hæggström E, Österberg K. Calibration of Fourier domain short coherence interferometer for absolute distance measurements. APPLIED OPTICS 2015; 54:4635-4639. [PMID: 26192496 DOI: 10.1364/ao.54.004635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/16/2015] [Indexed: 06/04/2023]
Abstract
We calibrated and determined the measurement uncertainty of a custom-made Fourier domain short coherence interferometer operated in laboratory conditions. We compared the optical thickness of two thickness standards and three coverslips determined with our interferometer to the geometric thickness determined by SEM. Using this calibration data, we derived a calibration function with a 95% confidence level system uncertainty of (5.9×10(-3)r+2.3) μm, where r is the optical distance in μm, across the 240 μm optical measurement range. The confidence limit includes contributions from uncertainties in the optical thickness, geometric thickness, and refractive index measurements as well as uncertainties arising from cosine errors and thermal expansion. The results show feasibility for noncontacting absolute distance characterization with micrometer-level accuracy. This instrument is intended for verifying the alignment of the discs of an accelerating structure in the possible future compact linear collider.
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22
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Bellini N, Cox MJ, Harper DJ, Stott SR, Ashok PC, Dholakia K, Kawaguchi S, King R, Horton T, Brown CTA. The application of optical coherence tomography to image subsurface tissue structure of Antarctic krill Euphausia superba. PLoS One 2014; 9:e110367. [PMID: 25310589 PMCID: PMC4195727 DOI: 10.1371/journal.pone.0110367] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/04/2014] [Indexed: 11/19/2022] Open
Abstract
Many small open ocean animals, such as Antarctic krill, are an important part of marine ecosystems. To discover what will happen to animals such as krill in a changing ocean, experiments are run in aquaria where conditions can be controlled to simulate water characteristics predicted to occur in the future. The response of individual animals to changing water conditions can be hard to observe, and with current observation techniques it is very difficult to follow the progress of an individual animal through its life. Optical coherence tomography (OCT) is an optical imaging technique that allows images at high resolution to be obtained from depths up to a few millimeters inside biological specimens. It is compatible with in vivo imaging and can be used repeatedly on the same specimens. In this work, we show how OCT may be applied to post mortem krill samples and how important physiological data such as shell thickness and estimates of organ volume can be obtained. Using OCT we find an average value for the thickness of krill exoskeleton to be (30±4) µm along a 1 cm length of the animal body. We also show that the technique may be used to provide detailed imagery of the internal structure of a pleopod joint and provide an estimate for the heart volume of (0.73±0.03) mm3.
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Affiliation(s)
- Nicola Bellini
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
| | - Martin J. Cox
- Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Danielle J. Harper
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
| | - Sebastian R. Stott
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
| | - Praveen C. Ashok
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
| | - Kishan Dholakia
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
| | - So Kawaguchi
- Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Robert King
- Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Tammy Horton
- National Oceanography Centre, University of Southampton Waterfront Campus, Southampton, United Kingdom
| | - Christian T. A. Brown
- SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, United Kingdom
- * E-mail:
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23
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Di Donato A, Criante L, LoTurco S, Farina M. Optical microcavity scanning 3D tomography. OPTICS LETTERS 2014; 39:5495-5498. [PMID: 25360911 DOI: 10.1364/ol.39.005495] [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 scanning optical microcavity is exploited to achieve lens-free 3D tomography of microfluidic channels. The microcavity, powered by a low-coherence source, is realized by approaching a cleaved fiber to few tens of micrometers over the sample. The interference of scattered waves inside the cavity shapes the transverse field distribution by focusing the beam and overcoming the diffraction limit due to the optical-fiber numerical aperture. The focusing effect is also preserved in the inner layers of the sample, allowing optical 3D tomography. Analysis of microfluidic channels was demonstrated through this noninvasive technique. Although the experimental setup recalls the well-known fiber-optic Fourier-domain common-path optical coherence tomography, the proposed method has intrinsic characteristics that distinguish it from the former one.
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24
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Kuchmizhak A, Gurbatov S, Nepomniaschii A, Vitrik O, Kulchin Y. High-quality fiber microaxicons fabricated by a modified chemical etching method for laser focusing and generation of Bessel-like beams. APPLIED OPTICS 2014; 53:937-43. [PMID: 24663275 DOI: 10.1364/ao.53.000937] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 01/16/2014] [Indexed: 05/20/2023]
Abstract
The fabrication method of the high-quality fiber microaxicons (FMAs) on the endface of the optical fiber was developed. Using several types of the commercially available optical fibers we experimentally demonstrated the fabrication of a high-quality FMA focusing a laser beam into a tiny spot with a FWHM≈0.6λ and Bessel-like field distribution. It was also demonstrated that choosing the appropriate chemical composition of the etching solution makes it possible to change the shape of the FMA tip from conical to hemispherical. This allows one to change the spatial distribution of the output laser beam, which can represent both the Bessel-like beam with a depth of focus of up to 49λ and a very tiny focal spot close to the diffraction limit size. Experimentally measured focusing characteristics of the fabricated FMAs obtained using a homemade collection-mode scanning near-field optical microscope setup demonstrate good agreement with numerical simulations based on the 3D finite-difference time-domain simulations.
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25
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Mahalati RN, Gu RY, Kahn JM. Resolution limits for imaging through multi-mode fiber. OPTICS EXPRESS 2013; 21:1656-68. [PMID: 23389151 DOI: 10.1364/oe.21.001656] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We experimentally demonstrate endoscopic imaging through a multi-mode fiber (MMF) in which the number of resolvable image features approaches four times the number of spatial modes per polarization propagating in the fiber. In our method, a sequence of random field patterns is input to the fiber, generating a sequence of random intensity patterns at the output, which are used to sample an object. Reflected power values are returned through the fiber and linear optimization is used to reconstruct an image. The factor-of-four resolution enhancement is due to mixing of modes by the squaring inherent in field-to-intensity conversion. The incoherent point-spread function (PSF) at the center of the fiber output plane is an Airy disk equivalent to the coherent PSF of a conventional diffraction-limited imaging system having a numerical aperture twice that of the fiber. All previous methods for imaging through MMF can only resolve a number of features equal to the number of modes. Most of these methods use localized intensity patterns for sampling the object and use local image reconstruction.
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Affiliation(s)
- Reza Nasiri Mahalati
- E. L. Ginzton Laboratory and Department of Electrical Engineering Stanford University, Stanford, CA 94305, USA.
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26
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Huang Y, Liu X, Song C, Kang JU. Motion-compensated hand-held common-path Fourier-domain optical coherence tomography probe for image-guided intervention. BIOMEDICAL OPTICS EXPRESS 2012; 3:3105-18. [PMID: 23243562 PMCID: PMC3521294 DOI: 10.1364/boe.3.003105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/25/2012] [Accepted: 10/29/2012] [Indexed: 05/04/2023]
Abstract
A motion-compensated, hand-held, common-path, Fourier-domain optical coherence tomography imaging probe has been developed for image-guided intervention during microsurgery. A hand-held prototype instrument was achieved by integrating an imaging fiber probe inside a stainless steel needle and attached to the ceramic shaft of a piezoelectric motor housed in an aluminum handle. The fiber probe obtains A-scan images. The distance information was extracted from the A-scans to track the sample surface distance and a fixed distance was maintained by a feedback motor control which effectively compensated hand tremor and target movements in the axial direction. Real-time data acquisition, processing, motion compensation, and image visualization and saving were implemented on a custom CPU-GPU hybrid architecture. We performed 10× zero padding to the raw spectrum to obtain 0.16 µm position accuracy with a compensation rate of 460 Hz. The root-mean-square error of hand-held distance variation from target position was measured to be 2.93 µm. We used a cross-correlation maximization-based shift correction algorithm for topology correction. To validate the system, we performed free-hand OCT M-scan imaging using various samples.
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27
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Dhawan AP, D'Alessandro B, Fu X. Optical imaging modalities for biomedical applications. IEEE Rev Biomed Eng 2012; 3:69-92. [PMID: 22275202 DOI: 10.1109/rbme.2010.2081975] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Optical photographic imaging is a well known imaging method that has been successfully translated into biomedical applications such as microscopy and endoscopy. Although several advanced medical imaging modalities are used today to acquire anatomical, physiological, metabolic, and functional information from the human body, optical imaging modalities including optical coherence tomography, confocal microscopy, multiphoton microscopy, multispectral endoscopy, and diffuse reflectance imaging have recently emerged with significant potential for non-invasive, portable, and cost-effective imaging for biomedical applications spanning tissue, cellular, and molecular levels. This paper reviews methods for modeling the propagation of light photons in a biological medium, as well as optical imaging from organ to cellular levels using visible and near-infrared wavelengths for biomedical and clinical applications.
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Affiliation(s)
- Atam P Dhawan
- Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA.
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28
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Krstajić N, Brown CTA, Dholakia K, Giardini ME. Tissue surface as the reference arm in Fourier domain optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:071305. [PMID: 22894466 DOI: 10.1117/1.jbo.17.7.071305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a simple method applicable to common-path Fourier domain optical coherence tomography (OCT) in which the tissue surface is used as the reference arm. We propose using aluminium hydroxide powder as a potential tissue surface diffuser to allow wider application of this method. This technique allows one to avoid placing a reference arm reflective element, such as glass plate, on tissue, and intrinsically avoids both coherent and complex conjugate mirror artifacts associated with glass plates. Aluminium hydroxide can be sprayed onto tissue using spray nozzles commonly found in endoscopes. The sensitivity of the tissue reference arm common-path OCT image is 94 dB for a 50-[micro sign]s charge-coupled device integration time, and 97.5 dB for a 200-[micro sign]s CCD integration time.
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Affiliation(s)
- Nikola Krstajić
- University of Edinburgh, School of Engineering, Institute for Integrated Micro and Nano Systems, Faraday Building, Kings Buildings, Mayfield Road, Edinburgh EH93JL, United Kingdom
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29
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Mahalati RN, Askarov D, Wilde JP, Kahn JM. Adaptive control of input field to achieve desired output intensity profile in multimode fiber with random mode coupling. OPTICS EXPRESS 2012; 20:14321-14337. [PMID: 22714494 DOI: 10.1364/oe.20.014321] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We develop a method for synthesis of a desired intensity profile at the output of a multimode fiber (MMF) with random mode coupling by controlling the input field distribution using a spatial light modulator (SLM) whose complex reflectance is piecewise constant over a set of disjoint blocks. Depending on the application, the desired intensity profile may be known or unknown a priori. We pose the problem as optimization of an objective function quantifying, and derive a theoretical lower bound on the achievable objective function. We present an adaptive sequential coordinate ascent (SCA) algorithm for controlling the SLM, which does not require characterizing the full transfer characteristic of the MMF, and which converges to near the lower bound after one pass over the SLM blocks. This algorithm is faster than optimizations based on genetic algorithms or random assignment of SLM phases. We present simulated and experimental results applying the algorithm to forming spots of light at a MMF output, and describe how the algorithm can be applied to imaging.
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Affiliation(s)
- Reza Nasiri Mahalati
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
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30
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Lorenser D, Yang X, Sampson DD. Ultrathin fiber probes with extended depth of focus for optical coherence tomography. OPTICS LETTERS 2012; 37:1616-8. [PMID: 22627514 DOI: 10.1364/ol.37.001616] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report on a novel scheme for extending the depth of focus (DOF) of ultrathin (125 μm diameter) fiber probes for optical coherence tomography (OCT) using a simple phase mask consisting of graded-index (GRIN) fiber. The technique is compatible with existing all-in-fiber probe fabrication techniques, and our simulations show that it can provide a DOF gain of ~2 at a modest ~5 dB reduction of peak sensitivity. In a prototype device using commercially available GRIN fiber, a DOF gain of 1.55 is obtained, validated by beam profiling and OCT imaging.
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Affiliation(s)
- Dirk Lorenser
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, WA 6009, Australia.
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31
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Steinvurzel P, Tantiwanichapan K, Goto M, Ramachandran S. Fiber-based Bessel beams with controllable diffraction-resistant distance. OPTICS LETTERS 2011; 36:4671-4673. [PMID: 22139279 DOI: 10.1364/ol.36.004671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We experimentally generate n=0 Bessel beams via higher-order cladding mode excitation with a long period fiber grating. Our method allows >99% conversion efficiency, wide or narrow conversion bandwidth, and accurate control of the number of rings in the beam. This latter property is equivalent to tuning the beam cone angle and allows for control of width and propagation distance of the center spot. We generate Bessel-like beams from LP(0,5) to LP(0,15) cladding modes and measure their propagation-invariant characteristics as a function of mode order, which match numerical simulations and a simple geometric model. This yields a versatile tool for tuning depth of focus out of fiber tips, with potential uses in endoscopic microscopy.
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Affiliation(s)
- Paul Steinvurzel
- Boston University, Department of Electrical and Computer Engineering, 8 Saint Mary’s Street, Boston, Massachusetts 02118, USA.
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32
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Fujiwara K, Matoba O. High-speed cross-sectional imaging of valuable documents using common-path swept-source optical coherence tomography. APPLIED OPTICS 2011; 50:H165-H170. [PMID: 22193003 DOI: 10.1364/ao.50.00h165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A common-path swept-source optical coherence tomography (SS-OCT) is a promising scheme for implementing a high-speed and stable OCT system. We investigate the capability of a common-path SS-OCT system to perform the cross-sectional imaging of valuable documents translated at high speed for the check of its security feature. The influence of transport speeds, up to 2000 mm/s, on the depth resolution and the signal intensity is experimentally evaluated using a SS-OCT system equipped with a swept source at a center wavelength of 1335 nm and with a sweep repetition rate of 50 kHz. The degradation of the measured signal is in good agreement with theory.
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Affiliation(s)
- Kazuo Fujiwara
- Research and Development Center, GLORY Ltd., 1-3-1 Shimoteno, Himeji, Hyogo 670-8567, Japan
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33
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Zhang K, Kang JU. Common-path low-coherence interferometry fiber-optic sensor guided microincision. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:095003. [PMID: 21950912 PMCID: PMC3188640 DOI: 10.1117/1.3622492] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We propose and demonstrate a common-path low-coherence interferometry (CP-LCI) fiber-optic sensor guided precise microincision. The method tracks the target surface and compensates the tool-to-surface relative motion with better than ± 5 μm resolution using a precision micromotor connected to the tool tip. A single-fiber distance probe integrated microdissector was used to perform an accurate 100 μm incision into the surface of an Intralipid phantom. The CP-LCI guided incision quality in terms of depth was evaluated afterwards using three-dimensional Fourier-domain optical coherence tomography imaging, which showed significant improvement of incision accuracy compared to free-hand-only operations.
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Affiliation(s)
- Kang Zhang
- Johns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland 21218, USA.
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34
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Ma N, Gunn-Moore F, Dholakia K. Optical transfection using an endoscope-like system. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:028002. [PMID: 21361709 DOI: 10.1117/1.3541781] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Optical transfection is a powerful method for targeted delivery of therapeutic agents to biological cells. A tightly focused pulsed laser beam may transiently change the permeability of a cell membrane to facilitate the delivery of foreign genetic material into cells. We report the first realization of an endoscope-like integrated system for optical transfection. An imaging fiber (coherent optical fiber bundle) with ∼ 6000 cores (pixels) embedded in a fiber cladding of ∼ 300 μm in diameter, produces an image circle (area) of ∼ 270 μm diam. This imaging fiber, with an ordered axicon lens array chemically etched at its exit face, is used for the delivery of a femtosecond laser to the cell membrane for optical transfection along with subcellular resolution imaging. A microcapillary-based microfluidic system for localized drug delivery was also combined in this miniature, flexible system. Using this novel system, a plasmid transfection efficiency up to ∼ 72% was obtained for CHO-K1 cells. This endoscope-like system opens a range of exciting applications, in particular, in the targeted in vivo optical microsurgery area.
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Affiliation(s)
- Nan Ma
- University of St. Andrews, School of Physics & Astronomy, St. Andrews, Fife KY16 9SS United Kingdom.
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35
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Villiger M, Lasser T. Image formation and tomogram reconstruction in optical coherence microscopy. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2010; 27:2216-28. [PMID: 20922012 DOI: 10.1364/josaa.27.002216] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this work we present a model for image formation in optical coherence microscopy. In the spectral domain detection, each wavenumber has a specific coherent transfer function that samples a different part of the object's spatial frequency spectrum. The reconstruction of the tomogram is usually accurate only in a short depth of field. Using numerical simulations based on the developed model, we identified two distinct mechanisms that influence the signal of out-of-focus sample information. Besides the lateral blurring induced through defocusing, an additional axial envelope contributing equally to the signal degradation was found.
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Affiliation(s)
- Martin Villiger
- Laboratoire d’Optique Biomédicale, Ecole Polytechnique Fédérale de Lausanne, Station 17, CH-1015 Lausanne, Switzerland.
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36
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Kang JU, Han JH, Liu X, Zhang K, Song CG, Gehlbach P. Endoscopic Functional Fourier Domain Common Path Optical Coherence Tomography for Microsurgery. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2010; 16:781-792. [PMID: 22899880 PMCID: PMC3418670 DOI: 10.1109/jstqe.2009.2031597] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A single-arm interferometer based optical coherence tomography (OCT) system known as common-path OCT (CPOCT) is rapidly progressing towards practical application. Due in part to the simplicity and robustness of its design, Fourier Domain CPOCT (FD-CP-OCT) offers advantages in many endoscopic sensing and imaging applications. FD-CP-OCT uses simple, interchangeable fiber optic probes that are easily integrated into small and delicate surgical tools. The system is capable of providing not only high resolution imaging but also optical sensing. Here, we report progress towards practical application of FD-CP-OCT in the setting of delicate microsurgical procedures such as intraocular retinal surgery. To meet the challenges presented by the microsurgical requirements of these procedures, we have developed and initiated the validation of applicable fiber optic probes. By integrating these probes into our developing imaging system, we have obtained high resolution OCT images and have also completed a demonstration of their potential sensing capabilities. Specifically, we utilize multiple SLEDs to demonstrate sub 3-micron axial resolution in water; we propose a technique to quantitatively evaluate the spatial distribution of oxygen saturation levels in tissue; and we present evidence supportive of the technology's surface sensing and tool guidance potential by demonstrating topological and motion compensation capabilities.
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Affiliation(s)
- Jin U Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA (phone: 410-516-8186; fax: 410-516-5566; )
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Han JH, Ilev IK, Kim DH, Song CG, Kang JU. Investigation of gold-coated bare fiber probe for in situ intra-vitreous coherence domain optical imaging and sensing. APPLIED PHYSICS. B, LASERS AND OPTICS 2010; 99:741-746. [PMID: 20567605 PMCID: PMC2887671 DOI: 10.1007/s00340-010-3910-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have investigated the usage of gold-plated bare fiber probes for in situ imaging of retinal layers and surrounding ocular tissues using time-domain common-path optical coherence tomography. The fabricated intra-vitreous gold-plated micro-fiber probe can be fully integrated with surgical tools working in close proximity to the tissue to provide subsurface images having a self-contained reference plane independent to the Fresnel reflection between the distal end of the probe and the following medium for achieving reference in typical common-path optical coherence tomography. We have fully characterized the probe in an aqueous medium equivalent to the vitreous humor in the eye and were able to differentiate various functional retinal tissue layers whose thickness is larger than the system's resolution.
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Affiliation(s)
- J-H Han
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA,
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Kang JU, Han JH, Liu X, Zhang K. Common-Path Optical Coherence Tomography for Biomedical Imaging and Sensing. ACTA ACUST UNITED AC 2010; 14:1-13. [PMID: 20657808 DOI: 10.3807/josk.2010.14.1.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This paper describes a development of a fiber optic common-path optical coherence tomography (OCT) based imaging and guided system that possess ability to reliably identify optically transparent targets that are on the micron scale; ability to maintain a precise and safe position from the target; ability to provide spectroscopic imaging; ability to imaging biological target in 3-D. The system is based on a high resolution fiber optic Common-Path OCT (CP-OCT) that can be integrated into various mini-probes and tools. The system is capable of obtaining >70K A-scan per second with a resolution better than 3 μm. We have demonstrated that the system is capable of one-dimensional real-time depth tracking, tool motion limiting and motion compensation, oxygen-saturation level imaging, and high resolution 3-D images for various biomedical applications.
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Affiliation(s)
- Jin U Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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Han JH, Kang JU, Song CG. Polarization sensitive subcutaneous and muscular imaging based on common path optical coherence tomography using near infrared source. J Med Syst 2009; 35:521-6. [PMID: 20703538 DOI: 10.1007/s10916-009-9388-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 10/05/2009] [Indexed: 11/26/2022]
Abstract
In this paper, we describe a polarization sensitive (PS) subcutaneous and muscular imaging system based on common path optical coherence tomography (CP-OCT) using a near infrared source. The axial and lateral resolutions of the PS-OCT system are 9 and 6 μm, respectively. The main goal of this work is to build a high-resolution and minimally invasive optical imager for examining various kinds of cutaneous substructures with intrinsic or form birefringence. The internal structural information is extracted by the real-time signal analysis (Fourier Transform) of the modulated spectral intensity depending on the beam and tissue birefringence. The preliminary results using fresh beef longissimus muscle and in vivo Rattus norvegicus (rat) show that it is possible to visualize the birefringence effect of the tissue collagen fibers in the samples in order to achieve superior image contrast and sensitivity for the detection of hidden dermal structures. Compared to conventional CP-OCT, the proposed PS-OCT system provides depth-resolved images, which reflect the tissue birefringence.
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Affiliation(s)
- Jae-Ho Han
- Department of Electrical and Computer Engineering, John Hopkins University, Baltimore, MD 21218, USA
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Han JH, Liu X, Song CG, Kang JU. Common path optical coherence tomography with fibre bundle probe. ELECTRONICS LETTERS 2009; 45:1110-1112. [PMID: 20454586 PMCID: PMC2863318 DOI: 10.1049/el.2009.1627] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A simple common path optical coherence tomography using a fibre optic bundle as a probe is demonstrated experimentally. The mechanical lateral scans are accomplished outside the specimen, proximal entrance of the fibre bundle, which eliminated the need for moving parts in the distal end of the probe. This feature allows the probe to be made submillimetre in size and easily integrated into surgical tools for intraoperative imaging. The axial and lateral resolutions of the system, and preliminary images of phantom samples, are reported.
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Affiliation(s)
- J-H Han
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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