1. Articles from Ryo Okamoto

    1-4 of 4
    1. 0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography

      0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography

      Quantum information technologies harness the intrinsic nature of quantum theory to beat the limitations of the classical methods for information processing and communication. Recently, the application of quantum features to metrology has attracted much attention. Quantum optical coherence tomography (QOCT), which utilizes two-photon interference between entangled photon pairs, is a promising approach to overcome the problem with optical coherence tomography (OCT): As the resolution of OCT becomes higher, degradation of the resolution due to dispersion within the medium becomes more critical. Here we report on the realization of 0.54  μ m resolution two-photon interference, which surpasses the current record resolution ...

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    2. Dispersion cancellation in high-resolution two-photon interference

      Dispersion cancellation in high-resolution two-photon interference

      The dispersion cancellation observed in Hong-Ou-Mandel (HOM) interference between frequency-entangled photon pairs has been the basis of quantum optical coherence tomography and quantum clock synchronization. Here we explore the effect of phase dispersion on ultranarrow HOM dips. We show that the higher-order dispersion, the linewidth of the pump laser, and the spectral shape of the parametric fluorescence have a strong effect on the dispersion cancellation in the high-resolution regime with several experimental verifications. Perfect dispersion cancellation with a linewidth of 3 μ m is also demonstrated through 25 mm of water.

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    3. Spectral dependence of ultra-low dark count superconducting single photon detector for the evaluation of broadband parametric fluorescence

      Spectral dependence of ultra-low dark count superconducting single photon detector for the evaluation of broadband parametric fluorescence
      Superconducting nanowire single photon detectors (SNSPD) have unique characteristics of ultra low dark counts and wide spectrum sensitivity. These natures are indispensable for the evaluation of ultra-broadband parametric fluorescence, which are used for the quantum optical coherence tomography and novel optical non-linear experiments. Here we report the spectral dependence of the detection efficiency of a meander type SNSPD device, having reduced strip width of 50 nm, over a wide spectrum range up to near infra-red wavelength. The fiber coupled, meander type device was fabricated using 6 nm thick Niobium nitride (NbN) nanowires of reduced strip width, 50 nm, patterned over ...
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      Mentions: Osaka University
    4. Generation of broadband spontaneous parametric fluorescence and its application to quantum optical coherence tomography

      Generation of broadband spontaneous parametric fluorescence and its application to quantum optical coherence tomography
      Optical coherence tomography (OCT) based on Michelson interferometer has widely been utilized in biology and medicine as a type of optical biopsy and quantum optical coherence tomography (QOCT) based on Hong-Ou-Mandel interferometer has recently been demonstrated. By use of quantum entangled photon pairs generated via spontaneous parametric down conversion (SPDC) process, axial resolution of QOCT can be better than that of OCT in principle for a source of same bandwidth and group velocity dispersion (GVD) effect for QOCT can be automatically cancelled thanks to the frequency correlation of entangled photon pairs. To realize high-resolution QOCT, we need a broadband quantum ...
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    1-4 of 4
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  2. Topics in the News

    1. (4 articles) Osaka University
    2. (3 articles) Nagoya University
    3. (3 articles) Norihiko Nishizawa
    4. (1 articles) Kyoto University Graduate School of Medicine
    5. (1 articles) Atsushi Tanaka
    6. (1 articles) University of Southern California
    7. (1 articles) UC Irvine
    8. (1 articles) Qifa Zhou
    9. (1 articles) K. Kirk Shung
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    Generation of broadband spontaneous parametric fluorescence and its application to quantum optical coherence tomography Spectral dependence of ultra-low dark count superconducting single photon detector for the evaluation of broadband parametric fluorescence Dispersion cancellation in high-resolution two-photon interference 0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography Optical imaging techniques could offer non-invasive method to measure swelling within the brain, new study finds Using Optical Coherence Tomography as a Surrogate of Measurements of Intracranial Pressure in Idiopathic Intracranial Hypertension Endoscopic imaging in inflammatory bowel disease: current developments and emerging strategies 2D Ultrasonic Array-based Optical Coherence Elastography Optical coherence tomography angiography in diabetic retinopathy: an updated review Flow signal change in polyps after anti-vascular endothelial growth factor therapy Line-field confocal optical coherence tomography-Practical applications in dermatology and comparison with established imaging methods Optical coherence tomography detection of changes in inner retinal and choroidal thicknesses in patients with early retinitis pigmentosa