1. Articles from Seok-Hyun Yun

    1-20 of 20
    1. Optical coherence tomographic measurements of the sound-induced motion of the ossicular chain in chinchillas: Additional modes of ossicular motion enhance the mechanical response of the chinchilla middle ear at higher frequencies

      Optical coherence tomographic measurements of the sound-induced motion of the ossicular chain in chinchillas: Additional modes of ossicular motion enhance the mechanical response of the chinchilla middle ear at higher frequencies

      Wavelength-swept optical coherence tomography (OCT) was used to scan the structure of cadaveric chinchilla ears in three dimensions with high spatial resolution and measure the sound-induced displacements of the entire OCT-visible lateral surfaces of the ossicles in the lateral-to-medial direction. The simultaneous measurement of structure and displacement allowed a precise match between the observed motion and its structural origin. The structure and measured displacements are consistent with previously published data. The coincident detailed structural and motion measurements demonstrate the presence of several frequency-dependent modes of ossicular motion, including: (i) rotation about an anteriorly-to-posteriorly directed axis positioned near the commonly defined ...

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    2. Measuring mechanical wave speed, dispersion, and viscoelastic modulus of the cornea using optical coherence elastography

      Measuring mechanical wave speed, dispersion, and viscoelastic modulus of the cornea using optical coherence elastography

      Acoustic wave velocity measurement based on optical coherence tomography (OCT) is a promising approach to assess the mechanical properties of biological tissues and soft materials. While studies to date have demonstrated proof of concept of different ways to excite and detect mechanical waves, the quantitative performance of this modality as mechanical measurement has been underdeveloped. Here, we investigate the frequency dependent measurement of the wave propagation in viscoelastic tissues, using a piezoelectric point-contact probe driven with various waveforms. We found that a frequency range of 2–10 kHz is a good window for corneal elastography, in which the lowest-order flexural ...

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    3. Mapping the phase and amplitude of ossicular chain motion using sound-synchronous optical coherence vibrography

      Mapping the phase and amplitude of ossicular chain motion using sound-synchronous optical coherence vibrography

      The sound-driven vibration of the tympanic membrane and ossicular chain of middle-ear bones is fundamental to hearing. Here we show that optical coherence tomography in phase synchrony with a sound stimulus is well suited for volumetric, vibrational imaging of the ossicles and tympanic membrane. This imaging tool — OCT vibrography — provides intuitive motion pictures of the ossicular chain and how they vary with frequency. Using the chinchilla ear as a model, we investigated the vibrational snapshots and phase delays of the manubrium, incus, and stapes over 100 Hz to 15 kHz. The vibrography images reveal a previously undescribed mode of motion ...

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    4. Apparatus, methods and storage medium for performing polarization-based quadrature demodulation in optical coherence tomography

      Apparatus, methods and storage medium for performing polarization-based quadrature demodulation in optical coherence tomography

      Apparatus, method and storage medium which can provide at least one first electro-magnetic radiation to a sample and at least one second electromagnetic radiation to a reference, such that the first and/or second electromagnetic radiations have a spectrum which changes over time. In addition, a first polarization component of at least one third radiation associated with the first radiation can be combined with a second polarization component of at least one fourth radiation associated with the second radiation with one another. The first and second polarizations may be specifically controlled to be at least approximately orthogonal to one another.

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    5. Process, arrangements and systems for providing frequency domain imaging of a sample

      Process, arrangements and systems for providing frequency domain imaging of a sample

      Exemplary apparatus, arrangement and method can be provided for obtaining information associated with an anatomical structure or sample using optical microscopy. A radiation can include first electromagnetic radiation(s) directed to an anatomical sample and at least one second electromagnetic radiation directed to a reference. A wavelength of the radiation can vary over time, and the wavelength can be shorter than approximately 1150 nm. An interference can be detected between third and forth radiations associated with the first, second and fourth radiation, respectively. At least one image corresponding to portion(s) of the sample can be generated using data associated ...

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    6. Apparatus, method and system for generating optical radiation from biological gain media

      Apparatus, method and system for generating optical radiation from biological gain media

      In one exemplary embodiment, an apparatus can be provided which includes at least one biological medium that causes gain. According to another exemplary embodiment, an arrangement can be provided which is configured to be provided in an anatomical structure. This exemplary arrangement can include at least one emitter having a cross-sectional area of at most 10 microns within the anatomical structure, and which is configured to generate at least one laser radiation. In a further exemplary embodiment, an apparatus can be provided which can include at least one medium which is configured to cause gain; and at least one optical ...

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    7. Apparatus, method and system for performing phase-resolved optical frequency domain imaging

      Apparatus, method and system for performing phase-resolved optical frequency domain imaging

      Apparatus, system and method are provided which utilize signals received from a reference and a sample. In particular, a radiation is provided which includes at least one first electro-magnetic radiation directed to the sample and at least one second electro-magnetic radiation directed to the reference. A frequency of the radiation varies over time. An interference can be detected between at least one third radiation associated with the first radiation and at least one fourth radiation associated with the second radiation. It is possible to obtain a particular signal associated with at least one phase of at least one frequency component ...

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    8. Numerical model of optical coherence tomographic vibrography imaging to estimate corneal biomechanical properties

      Numerical model of optical coherence tomographic vibrography imaging to estimate corneal biomechanical properties

      Most techniques measuring corneal biomechanics in vivo are biased by side factors. We demonstrate the ability of optical coherence tomographic (OCT) vibrography to determine corneal material parameters, while reducing current prevalent restrictions of other techniques (such as intraocular pressure (IOP) and thickness dependency). Modal analysis was performed in a finite-element (FE) model to study the oscillation response in isolated thin corneal flaps/eye globes and to analyse the dependency of the frequency response function on: corneal elasticity, viscoelasticity, geometry (thickness and curvature), IOP and density. The model was verified experimentally in flaps from three bovine corneas and in two enucleated ...

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    9. Process, system and software arrangement for a chromatic dispersion compensation using reflective layers in optical coherence tomography (OCT) imaging

      Process, system and software arrangement for a chromatic dispersion compensation using reflective layers in optical coherence tomography (OCT) imaging

      A system, process and software arrangement are provided to compensate for a dispersion in at least one portion of an image. In particular, information associated with the portion of the image is obtained. The portion of the image can be associated with an interference signal that includes a first electromagnetic radiation received from a sample and a second electromagnetic radiation received from a reference. The dispersion in the at least one portion of the image can be compensated by controlling a phase of at least one spectral component of the interference signal.

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    10. Methods And Arrangements For Analysis, Diagnosis, And Treatment Monitoring Of Vocal Folds By Optical Coherence Tomography

      Methods And Arrangements For Analysis, Diagnosis, And Treatment Monitoring Of Vocal Folds By Optical Coherence Tomography
      Exemplary embodiments of an apparatus and a method can be provided. For example, a first information can be obtained for at least one signal that is (i) at least partially periodic and (ii) associated with at least one structure. In addition, a second information associated with the structure can be generated at multiple time points within a single cycle of the at least one signal. The second information can include information for the structure below a surface thereof. Further, it is possible to generate a third information based on the first information and the second information, where the third information ...
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    11. System, method and arrangement which can use spectral encoding heterodyne interferometry techniques for imaging

      System, method and arrangement which can use spectral encoding heterodyne interferometry techniques for imaging
      Systems, arrangements and methods for obtaining three-dimensional imaging data are provided. For example, a broadband light source can provide a particular radiation. A first electro-magnetic radiation can be focused and diffracted, and then provided to at least one sample to generate a spectrally-encoded line. A second electro-magnetic radiation may be provided to a reference, which may include a double-pass rapidly-scanning optical delay, where the first and second electro-magnetic radiations can be based on the particular radiation. An interference between a third electro-magnetic radiation (associated with the first electro-magnetic radiation) and a fourth electro-magnetic radiation (associated with the second electro-magnetic radiation ...
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    12. Systems and methods for generating data based on one or more spectrally-encoded endoscopy techniques

      Systems and methods for generating data based on one or more spectrally-encoded endoscopy techniques
      Exemplary systems and methods for generating data associated with at least one portion of a sample can be provided. For example, according to one exemplary embodiment of such systems and methods, it is possible to provide a particular radiation using at least one first arrangement. The particular radiation can include at least one first electro-magnetic radiation directed to at least one sample and at least one second electro-magnetic radiation directed to a reference arrangement. The first radiation and/or the second radiation can comprise a plurality of wavelengths. The first electro-magnetic radiation can be spectrally dispersed along at least one ...
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    13. Methods, arrangements and systems for polarization-sensitive optical frequency domain imaging of a sample

      Methods, arrangements and systems for polarization-sensitive optical frequency domain imaging of a sample
      Arrangements and methods are provided for obtaining data associated with a sample. For example, at least one first electro-magnetic radiation can be provided to a sample and at least one second electro-magnetic radiation can be provided to a reference (e.g., a non-reflective reference). A frequency of such radiation(s) can repetitively vary over time with a first characteristic period. In addition, a polarization state of the first electro-magnetic radiation, the second electro-magnetic radiation, a third electro-magnetic radiation (associated with the first radiation) or a fourth electro-magnetic radiation (associated with the second radiation) can repetitively vary over time with a ...
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    14. Dynamic imaging of vocal fold oscillation with four-dimensional optical coherence tomography

      Dynamic imaging of vocal fold oscillation with four-dimensional optical coherence tomography

      Optical coherence tomography (OCT) can provide high-resolution ([sim]10-15 [mu]m/pixel) images of vocal fold microanatomy, as demonstrated previously. We explored physiologically triggered Fourier-domain OCT for imaging vocal folds during phonation. The goal is to visualize dynamic histological cross sections and four-dimensional data sets where multiple planes are displayed in synchronized motion. If feasible, this approach could be a useful research tool and spur development of new clinical instrumentation.A Fourier-domain, triggered OCT system was created and tested in experiments on excised calf larynges to obtain preliminary observations and characterize important factors affecting image quality.Larynges were imaged during ...

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    15. Method and apparatus for performing optical imaging using frequency-domain interferometry

      Method and apparatus for performing optical imaging using frequency-domain interferometry
      An apparatus and method are provided. In particular, at least one first electro-magnetic radiation may be provided to a sample and at least one second electro-magnetic radiation can be provided to a non-reflective reference. A frequency of the first and/or second radiations varies over time. An interference is detected between at least one third radiation associated with the first radiation and at least one fourth radiation associated with the second radiation. Alternatively, the first electro-magnetic radiation and/or second electro-magnetic radiation have a spectrum which changes over time. The spectrum may contain multiple frequencies at a particular time. In ...
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    16. Process and apparatus for a wavelength tuning source

      An apparatus and source arrangement for filtering an electromagnetic radiation can be provided which may include at least one spectral separating arrangement configured to physically separate one or more components of the electromagnetic radiation based on a frequency of the electromagnetic radiation. The apparatus and source arrangement may also have at least one continuously rotating optical arrangement which is configured to receive at least one signal that is associated with the one or more components. Further, the apparatus and source arrangement can include at least one beam selecting arrangement configured to receive the signal.
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    17. Fourier-domain optical coherence tomography: recent advances toward clinical utility

      With the advent of Fourier-domain techniques, optical coherence tomography (OCT) has advanced from high-resolution ‘point’ imaging over small fields-of-view to comprehensive microscopic imaging over three-dimensional volumes that are comparable to the dimensions of luminal internal organs. This advance has required the development of new lasers, improved spectrometers, minimally invasive catheters and endoscopes, and novel optical and signal processing strategies. In recent cardiovascular, ophthalmic, and gastrointestinal clinical studies, the capabilities of Fourier-domain OCT have enabled a new paradigm for diagnostic screening of large tissue areas, which addresses the shortcomings of existing technologies and focal biopsy.
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    18. Single-detector polarization-sensitive optical frequency domain imaging using high-speed intra A-line polarization modulation

      We demonstrate a novel high-speed polarization-sensitive optical frequency domain imaging system employing high-speed polarization modulation. Rapid and continuous polarization modulation of light prior to illumination of the sample is accomplished by shifting the frequency of one polarization ... [Opt. Lett. 33, 1330-1332 (2008)]
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    19. System and method for optical coherence imaging

      A system and method for imaging of a sample, e.g., biological sample, are provided. In particular, at least one source electro-magnetic radiation forwarded to the sample and a reference may be generated. A plurality of detectors may be used, at least one of the detectors capable of detecting a signal associated with a combination of at least one first electro-magnetic radiation received from the sample and at least one second electro-magnetic radiation received from the reference. At least one particular detector may have a particular electrical integration time, and can receive at least a portion of the signal for ...
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    20. High-speed polarization sensitive optical frequency domain imaging with frequency multiplexing

      W.Y. Oh, S.H. Yun, B.J. Vakoc, M. Shishkov, A.E. Desjardins, B.H. Park, J.F. de Boer, G.J. Tearney, B.E. Bouma. Polarization sensitive optical coherence tomography (PS-OCT) provides a cross-sectional image of birefringence in biological samples that is complementary in many applications to the standard reflectance-based image. Recent ex vivo studies have demonstrated that birefringence mapping enables the ... [Opt. Express 16, 1096-1103 (2008)]
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    1-20 of 20
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    1. (18 articles) Harvard University
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    Method and apparatus for performing optical imaging using frequency-domain interferometry Dynamic imaging of vocal fold oscillation with four-dimensional optical coherence tomography Methods, arrangements and systems for polarization-sensitive optical frequency domain imaging of a sample Systems and methods for generating data based on one or more spectrally-encoded endoscopy techniques System, method and arrangement which can use spectral encoding heterodyne interferometry techniques for imaging Structural abnormalities associated with glaucoma using swept-source optical coherence tomography in patients with systemic sclerosis Clinical presentation does not affect acute mechanical performance of the Novolimus-eluting bioresorbable vascular scaffold as assessed by optical coherence tomography Evaluating optical coherence tomography (OCT) findings as potential biomarkers in central nervous system (CNS) lymphoma with or without ocular involvement Polarization sensitive optical coherence tomography with single input for imaging depth-resolved collagen organizations Etanercept Therapy for Nails Psoriasis Monitoring With Noninvasive Imaging The Use of Optical Coherence Tomography to Asscess Water Transport Through The Urothelium of The Porcine Bladder Evaluation of the Effect of Covid-19 on Optic Disk and Macula with OCT and OCT-Angiography