1. Articles from Jason Ensher

    1-13 of 13
    1. Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye

      Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye

      Imaging of the human retina with high resolution is an essential step towards improved diagnosis and treatment control. In this paper, we introduce a compact, clinically user-friendly instrument based on swept source optical coherence tomography (SS-OCT). A key feature of the system is the realization of two different operation modes. The first operation mode is similar to conventional OCT imaging and provides large field of view (FoV) images (up to 45° × 30°) of the human retina and choroid with standard resolution. The second operation mode enables it to optically zoom into regions of interest with high transverse resolution using adaptive ...

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    2. Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      The cutaneous vasculature is involved in many diseases. Current clinical examination techniques, however, cannot resolve the human vasculature with all plexus in a non-invasive manner. By combining an optical coherence tomography system with angiography extension and an all optical photoacoustic tomography system, we can resolve in 3D the blood vessels in human skin for all plexus non-invasively. With a customized imaging unit that permits access to various parts of patients’ bodies, we applied our multimodality imaging system to investigate several different types of skin conditions. Quantitative vascular analysis is given for each of the dermatological conditions to show the potential ...

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    3. System and method of dynamic and adaptive creation of a wavelength continuous and prescribed wavelength versus time sweep from a laser

      System and method of dynamic and adaptive creation of a wavelength continuous and prescribed wavelength versus time sweep from a laser

      A system (10, 20) and method including a wavelength tuning mechanism and a laser path length tuning mechanism for reducing discontinuities in a sweep range. A processor (14) is coupled to a wavelength monitoring device (18) and the tuning mechanisms. The processor analyzes data from the wavelength monitor to adjust the wavelength tuning and cavity length tuning at discontinuities in the wavelength sweep to reduce the discontinuities.

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    4. System and method for creating and utilizing multivariate paths for ongoing simultaneous multi-dimensional control to attain single mode sweep operation in an electromagnetic radiation source

      System and method for creating and utilizing multivariate paths for ongoing simultaneous multi-dimensional control to attain single mode sweep operation in an electromagnetic radiation source

      A method for sweeping an electromagnetic radiation source (12) to produce single mode operation having an optimized side-mode suppression ratio over a continuous range of wavelengths within a prescribed temporal profile, the electromagnetic radiation source is configured to output electromagnetic radiation at a given wavelength based upon parameters. The method includes determining a set of parameter combinations that satisfy a condition for a desired set of wavelengths and a maximum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for transitioning from one wavelength to another wavelength. Combinations of select sub-paths provide a ...

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    5. Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Studies have proven the relationship between cutaneous vasculature abnormalities and dermatological disorders, but to image vasculature noninvasively in vivo , advanced optical imaging techniques are required. In this study, we imaged a palm of a healthy volunteer and three subjects with cutaneous abnormalities with photoacoustic tomography (PAT) and optical coherence tomography with angiography extension (OCTA). Capillaries in the papillary dermis that are too small to be discerned with PAT are visualized with OCTA. From our results, we speculate that the PA signal from the palm is mostly from hemoglobin in capillaries rather than melanin, knowing that melanin concentration in volar skin ...

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    6. System and method for generating and utilizing a valid sweep signal to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      System and method for generating and utilizing a valid sweep signal to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      A system and method for triggering data acquisition in a semiconductor laser system including outputting electromagnetic energy from the semiconductor laser over a range of wavelengths according to a signaling path. The signaling path includes a plurality of discrete data inputs to the semiconductor laser for outputting electromagnetic energy over a range of wavelengths and the signaling path includes one or more perturbances in transitioning from one wavelength to another wavelength along the signaling path. A series of triggering signals for input to a measurement system is generated by the semiconductor laser. The semiconductor laser also generates a series of ...

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    7. System and method of measurement frequency shifting to isolate external environmental conditions for interferometric dispersion measurements

      System and method of measurement frequency shifting to isolate external environmental conditions for interferometric dispersion measurements

      A system and method including a semiconductor laser source configured to output radiation over a range of wavelengths at a prescribed rate to a device under test. The prescribed rate is sufficiently above environmental frequency bands. A detector is configured to detect output radiation from the device under test to obtain a detected signal associated with at least one physical property associated with the incident radiation over the range of wavelengths at the prescribed rate. The detected signal includes environmental signal and target signal from the device under test. A processor isolates the environmental signal from the detected signal; and ...

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    8. System and method for generating and utilizing sample trigger blanking to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      System and method for generating and utilizing sample trigger blanking to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      A system and method for triggering data acquisition in a semiconductor laser system including outputting electromagnetic energy from the semiconductor laser over a range of wavelengths according to a signaling path. The signaling path includes a plurality of discrete data inputs to the semiconductor laser for outputting electromagnetic energy over a range of wavelengths and the signaling path includes one or more perturbances in transitioning from one wavelength to another wavelength along the signaling path. A series of triggering signals are generated for input to a measurement system by the semiconductor laser. The series of triggering signals include a non-uniform ...

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    9. System and method for generating and utilizing a valid sweep vector to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      System and method for generating and utilizing a valid sweep vector to obviate spurious data and increase sweep rate in an akinetic path-based swept laser

      A system and method for triggering data acquisition in a semiconductor laser system including outputting electromagnetic energy from the semiconductor laser over a range of wavelengths according to a signaling path. The signaling path includes a plurality of discrete data inputs to the semiconductor laser for outputting electromagnetic energy over a range of wavelengths and the signaling path includes one or more perturbances in transitioning from one wavelength to another wavelength along the signaling path. A series of triggering signals are generated for input to a measurement system by the semiconductor laser. The electromagnetic energy output from the semiconductor laser ...

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    10. System and method for optimization of coherence length of tunable laser sources

      System and method for optimization of coherence length of tunable laser sources

      A system and method for adjusting the coherence length of a tunable laser to optimize measurements and reduce artifacts. A tuning element of the laser system modulates, adjusts, or controls parameters associate with the tunable laser, such that the output wavelength of the tunable laser is modulated or adjusted over a wavelength range within a time interval. Modulation of the parameter has the effect of increasing a linewidth of the tunable laser.

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    11. System and method for generating an optimum side-mode suppression ratio continuous tuning path for a semiconductor tunable laser

      System and method for generating an optimum side-mode suppression ratio continuous tuning path for a semiconductor tunable laser

      A system and method to determine data sets of front mirror current, back mirror current and phase current that change the wavelength output by a semiconductor laser in a prescribed trajectory versus time, while maintaining the maximum side-mode suppression ratio at each point during the sweep.

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    12. System And Method For Improved Resolution, Higher Scan Speeds And Reduced Processing Time In Scans Involving SWEPT-WAVELENGTH Interferometry

      System And Method For Improved Resolution, Higher Scan Speeds And Reduced Processing Time In Scans Involving SWEPT-WAVELENGTH Interferometry

      A system and method for measuring an interferometric signal from a swept-wavelength interferometer by scanning a tunable laser source (12) over two wavelength ranges, whose centers are separated substantially more than the length of wavelength ranges. The spatial resolution of the measurement is determined by the inverse of the wavelength separation between a first and second wavelength region, as well as by the wavelength range of the first and second regions. An electronically tunable laser may be utilized to produce two wavelength ranges that are widely separated in wavelength. Such a system and method has wide applications to the fields ...

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    13. All-semiconductor high-speed akinetic swept-source for OCT

      All-semiconductor high-speed akinetic swept-source for OCT

      A novel swept-wavelength laser for optical coherence tomography (OCT) using a monolithic semiconductor device with no moving parts is presented. The laser is a Vernier-Tuned Distributed Bragg Reflector (VT-DBR) structure exhibiting a single longitudinal mode. All-electronic wavelength tuning is achieved at a 200 kHz sweep repetition rate, 20 mW output power, over 100 nm sweep width and coherence length longer than 40 mm. OCT point-spread functions with 45- 55 dB dynamic range are demonstrated; lasers at 1550 nm, and now 1310 nm, have been developed. Because the laser's long-term tuning stability allows for electronic sample trigger generation at equal ...

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    1-13 of 13
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  2. Topics in the News

    1. (13 articles) Michael P. Minneman
    2. (13 articles) Insight Photonic Solutions
    3. (3 articles) Medical University of Vienna
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    All-semiconductor high-speed akinetic swept-source for OCT System And Method For Improved Resolution, Higher Scan Speeds And Reduced Processing Time In Scans Involving SWEPT-WAVELENGTH Interferometry System and method for optimization of coherence length of tunable laser sources System and method for generating an optimum side-mode suppression ratio continuous tuning path for a semiconductor tunable laser System and method for generating and utilizing a valid sweep vector to obviate spurious data and increase sweep rate in an akinetic path-based swept laser System and method for generating and utilizing sample trigger blanking to obviate spurious data and increase sweep rate in an akinetic path-based swept laser System and method of measurement frequency shifting to isolate external environmental conditions for interferometric dispersion measurements System and method for generating and utilizing a valid sweep signal to obviate spurious data and increase sweep rate in an akinetic path-based swept laser Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye Intravitreal Ranibizumab Monotherapy or Combined with Laser for Diabetic Macular Edema (OCT guided study) Prospective evaluation of drug eluting self‐apposing stent for the treatment of unprotected left main coronary artery disease: 1‐year results of the TRUNC study