1. Norihiko Nishizawa

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    1. Mentioned In 38 Articles

    2. Signal-to-background ratio and lateral resolution in deep tissue imaging by optical coherence microscopy in the 1700 nm spectral band

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      Signal-to-background ratio and lateral resolution in deep tissue imaging by optical coherence microscopy in the 1700 nm spectral band
      We quantitatively investigated the image quality in deep tissue imaging with optical coherence microscopy (OCM) in the 1700 nm spectral band, in terms of the signal-to-background ratio (SBR) and lateral resolution. In this work, to demonstrate the benefits of using the 1700 nm spectral band for OCM imaging of brain samples, we compared the imaging quality of OCM en-face images obtained at the same position by using a hybrid 1300nm ...
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      Mentions: Nagoya University Norihiko Nishizawa

    3. High-spatial-resolution deep tissue imaging with spectral-domain optical coherence microscopy in the 1700-nm spectral band

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      High-spatial-resolution deep tissue imaging with spectral-domain optical coherence microscopy in the 1700-nm spectral band
      We present three-dimensional (3-D) high-resolution spectral-domain optical coherence microscopy (SD-OCM) by using a supercontinuum (SC) fiber laser source with 300-nm spectral bandwidth (full-width at half-maximum) in the 1700-nm spectral band. By using low-coherence interferometry with SC light and a confocal detection scheme, we realized lateral and axial resolutions of 3.4 and 3.8m in tissue ( n =1.38), respectively. This is, to the best of our knowledge, the highest ...
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      Mentions: Nagoya University Norihiko Nishizawa

    4. Wavelength Dependence of Ultrahigh-Resolution Optical Coherence Tomography Using Supercontinuum for Biomedical Imaging

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      Wavelength Dependence of Ultrahigh-Resolution Optical Coherence Tomography Using Supercontinuum for Biomedical Imaging
      Optical coherence tomography (OCT) is a noninvasive cross-sectional imaging technique with micrometer resolution. The theoretical axial resolution is determined by the center wavelength and bandwidth of the light source, and the wider the bandwidth, the higher the axial resolution. The characteristics of OCT imaging depend on the optical wavelength used. In this paper, we investigated the wavelength dependence of ultrahigh-resolution (UHR) OCT using a supercontinuum for biomedical imaging. Wideband, high-power ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

    5. Axial resolution and signal-to-noise ratio in deep-tissue imaging with 1.7-μm high-resolution optical coherence tomography with an ultrabroadband laser source

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      Axial resolution and signal-to-noise ratio in deep-tissue imaging with 1.7-μm high-resolution optical coherence tomography with an ultrabroadband laser source
      We investigated the axial resolution and signal-to-noise ratio (SNR) characteristics in deep-tissue imaging by 1.7 - m 1.7-m optical coherence tomography (OCT) with the axial resolution of 4.3 m 4.3m in tissue. Because 1.7 - m 1.7-m OCT requires a light source with a spectral width of more than 300 nm full-width at half maximum to achieve such high resolution, the axial resolution in the tissue ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

    6. Full-range ultrahigh-resolution spectral-domain optical coherence tomography in 1.7 µm wavelength region for deep-penetration and high-resolution imaging of turbid tissues

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      Full-range ultrahigh-resolution spectral-domain optical coherence tomography in 1.7 µm wavelength region for deep-penetration and high-resolution imaging of turbid tissues
      For the first time, we developed a full-range ultrahigh-resolution (UHR) spectral-domain optical coherence tomography (SD-OCT) technique working in the 1.7 m wavelength region. This technique allowed high-resolution, deep-tissue imaging. By using a supercontinuum source operating at a wavelength of 1.7 m, an axial resolution of 3.6 m in a tissue specimen was achieved. To enhance the imaging depth of UHR-SD-OCT, we performed full-range OCT imaging based on ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    7. Wideband ultrafast fiber laser sources for OCT and metrology

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      Wideband ultrafast fiber laser sources for OCT and metrology
      Fiber lasers, which use optical fibers as ideal waveguides, have been attracting a great deal of attention as stable, practical, and maintenance-free lasers. Using a combination of an ultrashort-pulse fiber laser and a nonlinear fiber, we can realize wideband highly functional ultrafast fiber laser sources. The generation of ultrashort pulses with wide wavelength tunability and supercontinua based on fiber lasers and nonlinear fibers has been demonstrated. These techniques are useful ...
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      Mentions: Nagoya University Norihiko Nishizawa

    8. Development of a Fiber-Optic Optical Coherence Tomography Probe for Intraocular Use

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      Development of a Fiber-Optic Optical Coherence Tomography Probe for Intraocular Use
      Purpose : To evaluate the performance of a newly developed 23-G optical coherence tomography (OCT) probe in animal and human eyes. Methods : The probe is a side-imaging OCT device with a scanning beam set 43 to the optical axis and a working distance of 1.5 to 2.0 mm. The performance of the OCT probe was tested during vitrectomy in porcine cadaver eyes and rabbit eyes in situ. Optical coherence ...
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      Mentions: Nagoya University Norihiko Nishizawa

    9. Optical coherence microscopy in 1700 nm spectral band for high-resolution label-free deep-tissue imaging

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      Optical coherence microscopy in 1700 nm spectral band for high-resolution label-free deep-tissue imaging
      Optical coherence microscopy (OCM) is a label-free, high-resolution, three-dimensional (3D) imaging technique based on optical coherence tomography (OCT) and confocal microscopy. Here, we report that the 1700-nm spectral band has the great potential to improve the imaging depth in high-resolution OCM imaging of animal tissues. Recent studies to improve the imaging depth in OCT revealed that the 1700-nm spectral band is a promising choice for imaging turbid scattering tissues due ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

    10. High-power supercontinuum generation using high-repetition-rate ultrashort-pulse fiber laser for ultrahigh-resolution optical coherence tomography in 1600 nm spectral band

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      High-power supercontinuum generation using high-repetition-rate ultrashort-pulse fiber laser for ultrahigh-resolution optical coherence tomography in 1600 nm spectral band
      We describe the generation of a high-power, spectrally smooth supercontinuum (SC) in the 1600 nm spectral band for ultrahigh-resolution optical coherence tomography (UHR-OCT). A clean SC was achieved by using a highly nonlinear fiber with normal dispersion properties and a high-quality pedestal-free pulse obtained from a passively mode-locked erbium-doped fiber laser operating at 182 MHz. The center wavelength and spectral width were 1578 and 172 nm, respectively. The output power ...
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      Mentions: Norihiko Nishizawa Hiroyuki Kawagoe

    11. Highly functional ultrashort pulse fiber laser sources and applications for optical coherence tomography

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      Highly functional ultrashort pulse fiber laser sources and applications for optical coherence tomography
      We have been investigating highly functional ultrashort pulse fiber laser sources for highly sensitive, ultrahigh resolution optical coherence tomography (UHR-OCT). The coherent, low-noise, and Gaussian like wideband super-continuum (SC) sources were developed at five different wavelength regions between 0.8 and 1.7 um in order to investigate the wavelength dependence of OCT imaging. A real-time imaging was achieved with spectral domain OCT system. A fiber laser based, rapid, widely ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

    12. 0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography

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      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 ...
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      Mentions: Osaka University Nagoya University Kyoto University Graduate School of Medicine

    13. Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography

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      Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography
      Optical coherence tomography is an optical imaging technique that performs non-destructive cross-sectional imaging of micrometer-scale structures in samples. In this report, we demonstrated the visualization of inner structures in tomato fruits and leaves with ultra-high resolution optical coherence tomography (UHR-OCT) using fiber based laser source with ultra-broadband continuous spectrum around 1.7 m wavelength. We confirmed that our UHR-OCT system allows us to perform cross-sectional imaging of tomato fruits and ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

    14. High-speed ultrahigh-resolution spectral domain optical coherence tomography using high-powersupercontinuum at 0.8 µm wavelength

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      High-speed ultrahigh-resolution spectral domain optical coherence tomography using high-powersupercontinuum at 0.8 µm wavelength
      We demonstrated high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT) in the 800 nm wavelength region. A high-power coherent supercontinuum (SC) and a high-speed line scan camera were used to construct a spectral domain OCT. The axial resolution was 3.1 m in air and 2.3 m in tissue. The dependence of sensitivity on the SC power and A-scan rate was examined. For the A-scan rate of 70 kHz, the ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe

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

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      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 ...
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      Mentions: Osaka University Nagoya University Norihiko Nishizawa

    16. Supercontinuum generation for ultrahigh-resolution optical coherence tomography at wavelength of 0.8µm using carbon nanotube fiber laser and similariton amplifier

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      Supercontinuum generation for ultrahigh-resolution optical coherence tomography at wavelength of 0.8µm using carbon nanotube fiber laser and similariton amplifier
      We demonstrated supercontinuum (SC) generation for ultrahigh-resolution optical coherence tomography (UHR-OCT) in the 0.8 m wavelength region using an ultrashort-pulse fiber laser system. An Er-doped ultrashort-pulse fiber laser with single-wall carbon nanotubes was developed as the seed pulse source. A 46 fs, highest quality, pedestal-free, clean, ultrashort pulse was generated with a similariton amplifier. Then, a 60 fs ideal ultrashort pulse was generated at a wavelength of 0.8 ...
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      Mentions: Nagoya University Norihiko Nishizawa Hiroyuki Kawagoe
    17. 1-15 of 38 1 2 3 »
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  4. About Norihiko Nishizawa

    Norihiko Nishizawa

    Norihiko Nishizawa is an Associate Professor in Department of Electrical Engineering and Computer Science and Graduate School of Engineering at Nagoya University in Japan.

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