1. Articles from kye-sung lee

    1-26 of 26
    1. Spectrally encoded common-path fiber-optic-based parallel optical coherence tomography

      Spectrally encoded common-path fiber-optic-based parallel optical coherence tomography

      We demonstrate a fiber-optic-based parallel optical coherence tomography (OCT) using spectrally encoded extended illumination with a common-path handheld probe, where the flexibility and robustness of the system are significantly improved, which is critical in the clinical environment. To the best of our knowledge, we present the first parallel OCT based on fiber optics including a fiber coupler with a sensitivity of 94 dB, which is comparable to that of point-scanning OCT. We also investigated the effect of the phase stability of the fiber-based interferometry on the parallel OCT system by comparing the common-path OCT with two-arm OCT. Using the homemade ...

      Read Full Article
      Mentions: Kye-Sung Lee
    2. Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy

      Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy

      Gabor-domain optical coherence microscopy (GD-OCM) is a volumetric high-resolution technique capable of acquiring three-dimensional (3-D) skin images with histological resolution. Real-time image processing is needed to enable GD-OCM imaging in a clinical setting. We present a parallelized and scalable multi-graphics processing unit (GPU) computing framework for real-time GD-OCM image processing. A parallelized control mechanism was developed to individually assign computation tasks to each of the GPUs. For each GPU, the optimal number of amplitude-scans (A-scans) to be processed in parallel was selected to maximize GPU memory usage and core throughput. We investigated five computing architectures for computational speed-up in processing ...

      Read Full Article
    3. Maximum-likelihood estimation in Optical Coherence Tomography in the context of the tear film dynamics

      Maximum-likelihood estimation in Optical Coherence Tomography in the context of the tear film dynamics

      Understanding tear film dynamics is a prerequisite for advancing the management of Dry Eye Disease (DED). In this paper, we discuss the use of optical coherence tomography (OCT) and statistical decision theory to analyze the tear film dynamics of a digital phantom. We implement a maximum-likelihood (ML) estimator to interpret OCT data based on mathematical models of Fourier-Domain OCT and the tear film. With the methodology of task-based assessment, we quantify the tradeoffs among key imaging system parameters. We find, on the assumption that the broadband light source is characterized by circular Gaussian statistics, ML estimates of 40 nm +/− 4 ...

      Read Full Article
    4. Nondestructive metrology by optical coherence tomography empowering manufacturing iterations of layered polymeric optical materials

      Nondestructive metrology by optical coherence tomography empowering manufacturing iterations of layered polymeric optical materials

      In recent years, there has been an ever-growing interest in exploring different optical materials and components to develop compact and effective optical systems. The design and fabrication of high-performance optics require nondestructive metrology techniques to inspect the samples. We have investigated the capability of optical coherence tomography (OCT) to nondestructively characterize layered polymeric materials. Using a custom developed Gabor-domain optical coherence microscopy system centered at 800 nm with 120 nm full width at half maximum enabling unprecedented 2 μ m resolution both laterally and axially in an 8     mm 3 volume, we investigated the internal structure of 50 μ m thick films ...

      Read Full Article
    5. Phantom study of tear film dynamics with optical coherence tomography and maximum-likelihood estimation

      Phantom study of tear film dynamics with optical coherence tomography and maximum-likelihood estimation

      In this Letter, we implement a maximum-likelihood estimator to interpret optical coherence tomography (OCT) data for the first time, based on Fourier-domain OCT and a two-interface tear film model. We use the root mean square error as a figure of merit to quantify the system performance of estimating the tear film thickness. With the methodology of task-based assessment, we study the trade-off between system imaging speed (temporal resolution of the dynamics) and the precision of the estimation. Finally, the estimator is validated with a digital tear-film dynamics phantom

      Read Full Article
    6. Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract ...

      Read Full Article
    7. Optical coherence tomography (OCT) apparatus, methods, and applications

      Optical coherence tomography (OCT) apparatus, methods, and applications

      A free-space Michelson Interferometer-based Dual Detection Frequency Domain-Optical Coherency Tomography (DD-FD-OCT) apparatus includes a non-polarizing beam splitter that can be used to misalign sample and reference beam paths to provide a stable .pi./2 phase shift between simultaneously detected interfering sample and reference beams to eliminate the mirror image created by Fourier transformation during image reconstruction. A hybrid fiber system Mach Zehnder Interferometer- and free-space Michelson Interferometer-based Dual Detection Frequency Domain-Doppler Optical Coherency Tomography (DD-FD-DOCT) apparatus provides higher power efficiency and thus better sensitivity compared to the free-space DD-FD-OCT. Both DD-FD-OCT systems enable functional imaging with the contrasts of Doppler ...

      Read Full Article
    8. Quantitative Measurement of Tear Film Dynamics with Optical Coherence Tomography and Statistical Decision Theory

      Quantitative Measurement of Tear Film Dynamics with Optical Coherence Tomography and Statistical Decision Theory

      Currently, there are about 40 to 60 million Americans suffering from Dry Eye Syndrome (DES); this serious public health problem will worsen with the explosive aging population created by baby boomers, where DES has a high incidence. However, the therapeutics for DES are elusive because our understanding of DES is so elementary, especially the correlation between symptoms and the diagnosis. Unfortunately, a quantitative diagnosis, which is the prerequisite to advance the management of DES, is yet to be realized. We are seeking the next breakthrough in DES management by providing a quantitative diagnosis, with the combination of optical coherence tomography ...

      Read Full Article
    9. Three-dimensional imaging of normal skin and nonmelanoma skin cancer with cellular resolution using Gabor domain optical coherence microscopy

      Three-dimensional imaging of normal skin and nonmelanoma skin cancer with cellular resolution using Gabor domain optical coherence microscopy

      We investigate morphological differences in three-dimensional (3-D) images with cellular resolution between nonmelanoma skin cancer and normal skin using Gabor domain optical coherence microscopy. As a result, we show for the first time cellular optical coherence images of 3-D features differentiating cancerous skin from normal skin. In addition, in vivo volumetric images of normal skin from different anatomic locations are shown and compared.

      Read Full Article
    10. Nondestructive metrology of layered polymeric optical materials using optical coherence tomography

      Nondestructive metrology of layered polymeric optical materials using optical coherence tomography

      In recent years, there has been an ever-growing interest in exploring novel, highly efficient optical materials to develop compact and effective optical components. The design and fabrication of high-performance optics require nondestructive metrology techniques to inspect the samples. We have investigated the capability of optical coherence tomography (OCT) to nondestructively characterize layered polymeric materials. Using a swept-source OCT system with a wavelength range of 1.25 - 1.41 μm, we achieved micron-scale three-dimensional visualization of the interior structures and details of the layered polymers. The 3D OCT imaging also enabled accurate identification of the locations of defects within the samples ...

      Read Full Article
    11. Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT

      Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT

      We analyze the three most common profiles of scanning functions for galvanometer-based scanners (GSs): the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e., frequency and amplitude). We study the differences of the output function of the GS measured as the positional error of the oscillatory mirror from the ideal function given by the input signal of the device. The limits in achieving the different types of scanning functions in terms of duty cycle and linearity are determined experimentally for the possible range of scan parameters. Of particular ...

      Read Full Article
    12. Micrometer axial resolution OCT for corneal imaging

      Micrometer axial resolution OCT for corneal imaging
      An optical coherence tomography (OCT) for high axial resolution corneal imaging is presented. The system uses 375 nm bandwidth (625 to 1000 nm) from a broadband supercontinuum light source. The system was developed in free space to minimize image quality degradation due to dispersion. A custom-designed spectrometer based on a Czerny Turner configuration was implemented to achieve an imaging depth of 1 mm. Experimentally measured axial resolution was 1.1 μm in corneal tissue and had a good agreement with the theoretically calculated resolution from the envelope of the spectral interference fringes. In vivo imaging was carried out and thin ...
      Read Full Article
    13. Systems and methods for generating a tunable laser beam

      Systems and methods for generating a tunable laser beam
      Systems and methods of generating a tunable laser beam are disclosed. An example method includes: generating coherent optical beams from a plurality of semiconductor optical amplifiers (SOAs); combining the coherent optical beams into a combined coherent optical beam; and tuning the combined beam to a selected frequency range to output a coherent optical beam having only the selected frequency range. In some embodiments, the SOAs are arranged in parallel within a resonant cavity, and each coherent optical beam has a different center wavelength that overlaps in bandwidth with another one of the coherent optical beams.
      Read Full Article
    14. Broadband Fourier-domain mode-locked lasers

      Broadband Fourier-domain mode-locked lasers
      Abstract  Broadband, high-speed wavelength-swept lasers can substantially enhance applications in optical coherence tomography, chemical spectroscopy, and fiber-optic sensing. We report the demonstration of Fourier-domain mode-lock lasers operating at about 90 kHz effective sweep rate over a 158 nm sweep range using a single-band design and over a 284 nm sweep range across the 1.3 μm to 1.5 μm wavelength spectrum using a unique broadband design. A novel dual-detection full-range Fourier-domain optical coherence tomography system is developed which provides 7 μm axial resolution (in air) at about 90 kHz axial scan rate for mirror-image resolved Doppler imaging in a ...
      Read Full Article
    15. Broadband astigmatism-corrected 
Czerny–Turner spectrometer

      Broadband astigmatism-corrected 
Czerny–Turner spectrometer
      e report an optical design for a low-cost optics, broadband, astigmatism-corrected practical spectrometer. An off-the-shelf cylindrical lens is used to remove astigmatism over the full bandwidth. Results show that better than 0.1 nm spectral resolution and more than 50% throughput were achieved over a bandwidth of 400 nm centered at 800 nm.
      Read Full Article
    16. Liquid lens enabled optical coherence microscope with Gabor fusion

      Liquid lens enabled optical coherence microscope with Gabor fusion
      A custom optical microscope with an integrated liquid lens to enable an extended depth imaging in biological tissue has been fabricated and shown to provide subcellular resolution using Gabor image fusion in an optical coherence tomography setup. In this paper, we report on the development and assessment path of this technology over the last few years. Specifically, we report on the optical design as well as the MTF prediction and experimental measurements of the new optical microscope head. The microscope head was integrated in a custom optical coherence microscopy setup that is presented. Images of an African frog tadpole, ex ...
      Read Full Article
    17. Doppler imaging with dual-detection full-range frequency domain optical coherence tomography

      Doppler imaging with dual-detection full-range frequency domain optical coherence tomography
      Most of full-range techniques for Frequency Domain Optical Coherence Tomography (FD-OCT) reported to date utilize the phase relation between consecutive axial lines to reconstruct a complex interference signal and hence may exhibit degradation in either mirror image suppression performance or detectable velocity dynamic range or both when monitoring a moving sample such as flow activity. We have previously reported a technique of mirror image removal by simultaneous detection of the quadrature components of a complex spectral interference called a Dual-Detection Frequency Domain OCT (DD-FD-OCT) [Opt. Lett. 35, 1058-1060 (2010)]. The technique enables full range imaging without any loss of acquisition ...
      Read Full Article
    18. Assessment of a liquid lens enabled in vivo optical coherence microscope

      Assessment of a liquid lens enabled in vivo optical coherence microscope
      The optical aberrations induced by imaging through skin can be predicted using formulas for Seidel aberrations of a plane-parallel plate. Knowledge of these aberrations helps to guide the choice of numerical aperture (NA) of the optics we can use in an implementation of Gabor domain optical coherence microscopy (GD-OCM), where the focus is the only aberration adjustment made through depth. On this basis, a custom-designed, liquid-lens enabled dynamic focusing optical coherence microscope operating at 0.2 NA is analyzed and validated experimentally. As part of the analysis, we show that the full width at half-maximum metric, as a characteristic descriptor ...
      Read Full Article
    19. Dual detection full range frequency domain optical coherence tomography

      Dual detection full range frequency domain optical coherence tomography
      It has been shown that frequency domain optical coherence tomography (FD-OCT) systems achieve higher sensitivities compared to time domain optical coherence tomography (OCT) systems. However, the obscure object structure due to the mirror image generated by the Fourier transform is one of the remaining issues in the FD-OCT. We designed and developed what we believe to be a novel full range FD-OCT system that we refer to as the dual detection full range frequency domain optical coherence tomography (DD-FDOCT) that enables the instantaneous retrieval of quadrature components of the complex interferometric signal. The DD-FDOCT system enables full range imaging without ...
      Read Full Article
    20. Gabor-based fusion technique for Optical Coherence Microscopy

      Gabor-based fusion technique for Optical Coherence Microscopy
      We recently reported on an Optical Coherence Microscopy technique, whose innovation intrinsically builds on a recently reported - 2 μm invariant lateral resolution by design throughout a 2 mm cubic full-field of view - liquid-lens-based dynamic focusing optical probe [Murali et al.,Optics Letters 34, 145-147, 2009]. We shall report in this paper on the image acquisition enabled by this optical probe when combined with an automatic data fusion method developed and described here to produce an in-focus high resolution image throughout the imaging depth of the sample. An African frog tadpole (Xenopus laevis) was imaged with the novel probe and the ...
      Read Full Article
    21. Gabor domain optical coherence microscopy

      Gabor domain optical coherence microscopy
      In this paper, we present a developing technology targeted at clinical imaging, Gabor Domain Optical Coherence Microscopy (GD-OCM), which combines the high resolution imaging of optical coherence microscopy (OCM), high imaging speed of Fourier domain optical coherence tomography (FD-OCT), and invariant lateral resolution of our custom designed dynamic focusing objective. A high lateral resolution optical design of a dynamic-focusing optical probe with no moving parts, which provides an invariant resolution of currently < 3 µm across a 2mm full-field of view and 2mm imaging depth, is presented. Furthermore, an acquisition scheme (using the probe) that is capable of performing automatic real ...
      Read Full Article
    22. Dual-reference full-range frequency domain optical coherence tomography

      Dual-reference full-range frequency domain optical coherence tomography
      It has been shown that frequency domain optical coherence tomography (FD-OCT) systems achieve higher sensitivities compared to time domain OCT systems. However, the obscure object structure due to the mirror image generated by the Fourier transform is one of the main problems in FD-OCT. We designed and developed a novel full range FD-OCT system that we refer to as the dual-reference full-range FD-OCT (DR-FDOCT) that enables doubling the imaging depth by removing mirror images generated from the Fourier transform of the detected real-valued spectra. The DR-FDOCT system enables full-range imaging without any loss of speed and is less sensitive to ...
      Read Full Article
    23. Gabor domain optical coherence microscopy

      Gabor domain optical coherence microscopy
      Optical Coherence Microscopy (OCM) is an emerging technology capable of depth sectioning of biological tissue at the micrometer scale. In this paper, we propose a developing technology we call Gabor Domain Optical Coherence Microscopy (GD-OCM), whose innovation is two folds: (1) A high lateral resolution optical design of a dynamic-focusing optical probe with no moving parts, which provides an invariant resolution of currently 3 µm across a 2mm full-field of view and 2mm imaging depth by design; (2) An acquisition scheme (using the probe) that is capable of performing automatic data fusion to render an in-focus high resolution image throughout ...
      Read Full Article
    24. Determination of the coherency matrix of a broadband stochastic electromagnetic light beam

      Determination of the coherency matrix of a broadband stochastic electromagnetic light beam

      The statistical ensemble of a fluctuating, statistically-stationary electromagnetic light beam is presented in terms of a 2 2 matrix, so-called coherency matrix. The method to determine such matrix for a quasi-monochromatic light beam has been proposed for many years. In this paper, we demonstrate that the method needs to be only slightly modified to determine the matrix elements of a broadband stochastic electromagnetic light beam, if one uses the representation of statistical wave fields in the space-frequency domain. The implementation of the method is demonstrated, and the coherency matrix measurement is validated using a well-defined elliptically polarized beam.

      Read Full Article
    25. Bessel beam spectral-domain high-resolution optical coherence tomography with micro-optic axicon providing extended focusing range

      Bessel beam spectral-domain high-resolution optical coherence tomography with micro-optic axicon providing extended focusing range
      Endoscopic imaging in tubular structures, such as the tracheobronchial tree, could benefit from imaging optics with an extended depth of focus (DOF) to accommodate the varying sizes of tubular structures across patients and along the tree within the same patient. Yet the extended DOF needs to be accomplished without sacrificing resolution while maintaining sufficient sensitivity and speed of imaging. In this Letter, we report on the measured resolution and sensitivity achieved with a custom-made micro-optic axicon lens designed to theoretically achieve an 8 mm DOF. A measured invariant resolution of 8 m is demonstrated across a 4 mm measured DOF ...
      Read Full Article
    26. Optical design of a dynamic focus catheter for high-resolution endoscopic optical coherence tomography

      Optical design of a dynamic focus catheter for high-resolution endoscopic optical coherence tomography
      The optical system design of a dynamic focus endoscopic probe for optical coherence tomography is reported. The dynamic focus capability is based on a liquid lens technology that provides variable focus by changing its curvatures in response to an electric field variation. The effects of a cylindrical exit window present, in practice, for a catheter were accounted for. Degradation in image quality caused by this window was corrected to get diffraction limited imaging performance. As a result, the dynamically focusing catheter with a lateral resolution ranging from 4 to 6 μm through an ∼5mm imaging distance was designed without mechanically ...
      Read Full Article
    1-26 of 26
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (26 articles) Kye-Sung Lee
    2. (25 articles) Jannick P. Rolland
    3. (19 articles) University of Rochester
    4. (17 articles) Panomsak Meemon
    5. (13 articles) University of Central Florida
    6. (7 articles) Kevin P. Thompson
    7. (6 articles) Supraja Murali
    8. (6 articles) Optical Research Associates
    9. (5 articles) University of Arizona
    10. (3 articles) Micron Optics
  3. Popular Articles

  4. Picture Gallery

    Optical design of a dynamic focus catheter for high-resolution endoscopic optical coherence tomography Dual-reference full-range frequency domain optical coherence tomography Gabor domain optical coherence microscopy Gabor-based fusion technique for Optical Coherence Microscopy Dual detection full range frequency domain optical coherence tomography Assessment of a liquid lens enabled in vivo optical coherence microscope Gabor domain optical coherence microscopy Liquid lens enabled optical coherence microscope with Gabor fusion Broadband astigmatism-corrected 
Czerny–Turner spectrometer Broadband Fourier-domain mode-locked lasers Optical coherence tomography in an eyelid lesion due to Molluscum contagiosum Lung adenocarcinoma choroidal metastasis studied by optical coherence tomography angiography