1. Vijay Jayaraman

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    1. Mentioned In 49 Articles

    2. Widely tunable swept source

      Widely tunable swept source
      A high-speed, single-mode, high power, reliable and manufacturable wavelength-tunable light source operative to emit wavelength tunable radiation over a wavelength range contained in a wavelength span between about 950 nm and about 1150 nm, including a vertical cavity laser (VCL), the VCL having a gain region with at least one compressively strained quantum well containing Indium, Gallium, and Arsenic.
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    3. Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source

      Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source
      Endoscopic optical coherence tomography (OCT) instruments are mostly side viewing and rely on at least one proximal scan, thus limiting accuracy of volumetric imaging and en face visualization. Previous forward-viewing OCT devices had limited axial scan speeds. We report a forward-viewing fiber scanning 3D-OCT probe with 900 m field of view and 5 m transverse resolution, imaging at 1 MHz axial scan rate in the human gastrointestinal tract. The probe ...
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    4. Tunable laser array system

      Tunable laser array system
      A system for swept source optical coherence tomography, the system including a light source emitting multiplexed wavelength-swept radiation over a total wavelength range, the light source including N wavelength-swept vertical cavity lasers (VCL) emitting N tunable VCL outputs having N wavelength trajectories, a combiner for combining the N tunable VCL optical outputs into a common optical path to create the multiplexed wavelength-swept radiation, a splitter for splitting the multiplexed wavelength-swept ...
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    5. Cubic meter volume optical coherence tomography

      Cubic meter volume optical coherence tomography
      Optical coherence tomography (OCT) is a powerful three-dimensional (3D) imaging modality with micrometer-scale axial resolution and up to multi-GigaVoxel/s imaging speed. However, the imaging range of high-speed OCT has been limited. Here, we report 3D OCT over cubic meter volumes using a long coherence length, 1310 nm vertical-cavity surface-emitting laser and silicon photonic integrated circuit dual-quadrature receiver technology combined with enhanced signal processing. We achieved 15 m depth resolution ...
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    6. Volumetric Mapping of Barrett’s Esophagus and Dysplasia With en face Optical Coherence Tomography Tethered Capsule

      Volumetric Mapping of Barrett’s Esophagus and Dysplasia With en face Optical Coherence Tomography Tethered Capsule
      To the Editor: Dysplasia in Barretts Esophagus (BE) is patchy ( 1 ) and sometimes missed by random biopsies. Optical coherence tomography (OCT) can image large areas of the esophagus; however, slow imaging speeds in earlier studies limited visualization to cross-sections. Cross-sectional OCT detected high-grade dysplasia with sensitivity / specificity of ~80 % ( 2 , 3 ). Tethered OCT capsules were demonstrated for cross-sectional imaging in unsedated screening to detect BE ( 4 , 5 ). Our group recently ...
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    7. ULTRAHIGH SPEED SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL AND CHORIOCAPILLARIS ALTERATIONS IN DIABETIC PATIENTS WITH AND WITHOUT RETINOPATHY

      ULTRAHIGH SPEED SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL AND CHORIOCAPILLARIS ALTERATIONS IN DIABETIC PATIENTS WITH AND WITHOUT RETINOPATHY
      Purpose: To investigate the utility of ultrahigh speed, swept source optical coherence tomography angiography in visualizing retinal microvascular and choriocapillaris (CC) changes in diabetic patients. Methods: The study was prospective and cross-sectional. A 1,050 nm wavelength, 400 kHz A-scan rate swept source optical coherence tomography prototype was used to perform volumetric optical coherence tomography angiography of the retinal and CC vasculatures in diabetic patients and normal subjects. Sixty-three eyes ...
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    8. Choroidal Neovascularization Analyzed on Ultrahigh-Speed Swept-Source Optical Coherence Tomography Angiography Compared to Spectral-Domain Optical Coherence Tomography Angiography

      Choroidal Neovascularization Analyzed on Ultrahigh-Speed Swept-Source Optical Coherence Tomography Angiography Compared to Spectral-Domain Optical Coherence Tomography Angiography
      Purpose To compare visualization of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) using an ultrahigh-speed swept-source (SS) optical coherence tomography angiography (OCTA) prototype vs a spectral-domain (SD) OCTA device. Design Comparative analysis of diagnostic instruments. Methods Patients were prospectively recruited to be imaged on SD OCT and SS OCT devices on the same day. The SD OCT device employed is the RTVue Avanti (Optovue, Inc, Fremont, California, USA ...
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    9. Amplified widely tunable short cavity laser

      Amplified widely tunable short cavity laser
      An amplified tunable source includes a short-cavity laser coupled to an optical amplifier for high power, spectrally shaped operation. The short-cavity laser is coupled to a quantum well semiconductor optical amplifier with two quantum states for broadened gain. Two preferred wavelength ranges of the amplified tunable source include 1200-1400 nm and 800-1100 nm. Also disclosed is the short cavity tunable laser coupled to a fiber amplifier. Various combinations of tunable ...
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    10. Tunable short cavity laser sensor

      Tunable short cavity laser sensor
      Optical systems employ a tunable source which includes a short cavity laser with a large free spectral range cavity, fast tuning response, and single transverse and longitudinal mode operation. Systems for optical spectroscopy with optimized scanning, a system for optical beam steering and a system for a tunable local oscillator are disclosed.
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    11. Polarization stable widely tunable short cavity laser

      Polarization stable widely tunable short cavity laser
      A tunable source includes a short-cavity laser optimized for performance and reliability in SSOCT imaging systems, spectroscopic detection systems, and other types of detection and sensing systems. A short cavity laser with a large free spectral range cavity, fast tuning response and single transverse, longitudinal and polarization mode operation is disclosed. Methods for obtaining polarization stable operation of the tunable source are presented.
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    12. Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

      Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter
      We demonstrate a micromotor balloon imaging catheter for ultrahigh speed endoscopic optical coherence tomography (OCT) which provides wide area, circumferential structural and angiographic imaging of the esophagus without contrast agents. Using a 1310 nm MEMS tunable wavelength swept VCSEL light source, the system has a 1.2 MHz A-scan rate and ~8.5 m axial resolution in tissue. The micromotor balloon catheter enables circumferential imaging of the esophagus at 240 ...
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    13. Choroidal neovascularization analyzed on ultra-high speed swept source optical coherence tomography angiography compared to spectral domain optical coherence tomography angiography

      Choroidal neovascularization analyzed on ultra-high speed swept source optical coherence tomography angiography compared to spectral domain optical coherence tomography angiography
      Purpose To compare visualization of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) using an ultra-high speed swept-source (SS)-optical coherence tomography angiography (OCTA) prototype versus a spectral-domain (SD)-OCTA device. Design Comparative analysis of diagnostic instruments. Methods Patients were prospectively recruited to be imaged on SD-OCT and SS-OCT devices on the same day. The SD-OCT device employed is the RTVue Avanti that operates at 840nm wavelength and 70 ...
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    14. Ultrahigh-Speed, Swept-Source Optical Coherence Tomography Angiography in Nonexudative Age-Related Macular Degeneration with Geographic Atrophy

      Ultrahigh-Speed, Swept-Source Optical Coherence Tomography Angiography in Nonexudative Age-Related Macular Degeneration with Geographic Atrophy
      Purpose To investigate ultrahigh-speed, swept-source optical coherence tomography (SSOCT) angiography for visualizing vascular changes in eyes with nonexudative age-related macular degeneration (AMD) with geographic atrophy (GA). Design Observational, prospective, cross-sectional study. Participants A total of 63 eyes from 32 normal subjects and 12 eyes from 7 patients with nonexudative AMD with GA. Methods A 1050-nm, 400-kHz A-scan rate SSOCT system was used to perform volumetric optical coherence tomography angiography (OCTA ...
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    15. Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging

      Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging
      In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at ...
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    16. Feature Of The Week 03/08/2015: Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature

      Feature Of The Week 03/08/2015: Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature
      Endoscopic imaging technologies such as confocal laser endomicroscopy (CLE) and narrowband imaging (NBI) have been used to investigate vascular changes as hallmarks of early cancer in the GI tract. However, the limited frame rate and field of view make CLE imaging sensitive to motion artifacts, whereas NBI has limited resolution and visualizes only the surface vascular pattern. Endoscopic optical coherence tomography (OCT) enables high speed volumetric imaging of subsurface features ...
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    17. 1-15 of 49 1 2 3 4 »
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  2. About Vijay Jayaraman

    Vijay Jayaraman

    Vijaysekhar Jayaraman is the founder of Praevium Research, and principal investigator on a number of Praevium’s SBIR efforts. He received his BS/MS in Electrical Engineering from the Massachusetts Institute of Technology in 1985, and a Ph.D. in Electrical Engineering from University of California, Santa Barbara in 1994. From 1985-1988, Dr. Jayaraman was a staff member at MIT Lincoln Laboratory, where he contributed to the development of a space-based optical heterodyne communication system. Prior to founding Praevium Research in 2001, Dr. Jayaraman’s notable accomplishments included the first demonstration of the SGDBR tunable laser while a graduate student at UCSB. This device has since been commercialized by a large telecommunications company. Dr. Jayaraman also contributed to the early  development development of electrically and optically pumped 1300 nm VCSELs while employed at Optical Concepts/W.L Gore and associates and UCSB.

  3. Quotes

    1. MEMS-VCSELs have previously demonstrated speed and coherence length advantages for SS-OCT, but questions remained as to whether MEMS-VCSEL tuning range could compete with widely tunable externalcavity lasers...We believe that this work demonstrates for the first time that MEMS-VCSEL tuning range can be on a par with these other devices...We hope to see a renaissance in the MEMS-VCSEL field...We anticipate new wavelength regimes and wider tuning ranges will be reported in the next few years, as well as new spectroscopic applications. We also anticipate significant cost reductions as we take advantage of Thorlabs’ volume semiconductor manufacturing. We look forward to seeing MEMS-VCSELs become an established commercial product for both medical and spectroscopic applications over the next decade.
      In A Clean Sweep for MEMS-VCSELs
    2. Though MEMs VCSELs first emerged for telecom, we believe OCT could become their highest impact application.
      In Praevium Research, Thorlabs, & MIT Demonstrate High Performance Swept Source Laser for OCT and Other Applications