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4 results on '"Yuma Hayashi"'

2. Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging

Author

Kunio Miyaji, Yoshimasa Sugimoto, Sho Yamauchi, Eiichiro Watanabe, Kenji Furuki, Naoki Ikeda, David T. D. Childs, Yuma Hayashi, Yoichi Oikawa, Richard A. Hogg, Hirotaka Ohsato, and Nobuhiko Ozaki

Subjects
Materials science, Acoustics and Ultrasonics, 02 engineering and technology, Electroluminescence, 01 natural sciences, law.invention, Optical coherence tomography, law, 0103 physical sciences, medicine, 010302 applied physics, medicine.diagnostic_test, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Superluminescent diode, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Wavelength, Quantum dot, Optoelectronics, 0210 nano-technology, business, Luminescence, Waveguide, Molecular beam epitaxy
Abstract

We developed a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) and demonstrated high-axial-resolution optical coherence tomography (OCT) imaging using this QD-based SLD (QD-SLD). The QD-SLD utilized InAs QDs with controlled emission wavelengths as a NIR broadband light emitter, and a tilted waveguide with segmented electrodes was prepared for edge-emitting broadband electroluminescence (EL) spanning approximately 1–1.3 μm. The bandwidth of the EL spectrum was increased up to 144 nm at a temperature of 25 °C controlled using a thermoelectric cooler. The inverse Fourier transform of the EL spectrum predicted a minimum resolution of 3.6 μm in air. The QD-SLD was subsequently introduced into a spectral-domain (SD)-OCT setup, and SD-OCT imaging was performed for industrial and biological test samples. The OCT images obtained using the QD-SLD showed an axial resolution of ~4 μm, which was almost the same as that predicted from the spectrum. This axial resolution is less than the typical size of a single biological cell (~5 μm), and the practical demonstration of high-axial-resolution OCT imaging shows the application of QD-SLDs as a compact OCT light source, which enables the development of a portable OCT system.

Published
2019

3. Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

Author

Nobuhiko Ozaki, Yuma Hayashi, Yoshimasa Sugimoto, Richard A. Hogg, Shingo Kanehira, Naoki Ikeda, and Shunsuke Ohkouchi

Subjects
Materials science, Physics::Optics, 02 engineering and technology, Substrate (electronics), 01 natural sciences, Inorganic Chemistry, Condensed Matter::Materials Science, Optics, Optical coherence tomography, 0103 physical sciences, Broadband, Materials Chemistry, medicine, Quantum, 010302 applied physics, medicine.diagnostic_test, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Wavelength, Optoelectronics, 0210 nano-technology, business, Layer (electronics), Intensity (heat transfer), Molecular beam epitaxy
Abstract

We obtained a high-intensity and broadband emission centered at ~1 µm from InGaAs quantum three-dimensional (3D) structures grown on a GaAs substrate using molecular beam epitaxy. An InGaAs thin layer grown on GaAs with a thickness close to the critical layer thickness is normally affected by strain as a result of the lattice mismatch and introduced misfit dislocations. However, under certain growth conditions for the In concentration and growth temperature, the growth mode of the InGaAs layer can be transformed from two-dimensional to 3D growth. We found the optimal conditions to obtain a broadband emission from 3D structures with a high intensity and controlled center wavelength at ~1 µm. This method offers an alternative approach for fabricating a broadband near-infrared light source for telecommunication and medical imaging systems such as for optical coherence tomography.

Published
2017

4. Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging.

Author

Nobuhiko Ozaki, Sho Yamauchi, Yuma Hayashi, Eiichiro Watanabe, Hirotaka Ohsato, Naoki Ikeda, Yoshimasa Sugimoto, Kenji Furuki, Yoichi Oikawa, Kunio Miyaji, David T D Childs, and Richard A Hogg

Subjects
OPTICAL coherence tomography, ELECTROLUMINESCENCE, QUANTUM dots, LIGHT sources, DIODES, FOURIER transforms
Abstract

We developed a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) and demonstrated high-axial-resolution optical coherence tomography (OCT) imaging using this QD-based SLD (QD-SLD). The QD-SLD utilized InAs QDs with controlled emission wavelengths as a NIR broadband light emitter, and a tilted waveguide with segmented electrodes was prepared for edge-emitting broadband electroluminescence (EL) spanning approximately 1–1.3 μm. The bandwidth of the EL spectrum was increased up to 144 nm at a temperature of 25 °C controlled using a thermoelectric cooler. The inverse Fourier transform of the EL spectrum predicted a minimum resolution of 3.6 μm in air. The QD-SLD was subsequently introduced into a spectral-domain (SD)-OCT setup, and SD-OCT imaging was performed for industrial and biological test samples. The OCT images obtained using the QD-SLD showed an axial resolution of ~4 μm, which was almost the same as that predicted from the spectrum. This axial resolution is less than the typical size of a single biological cell (~5 μm), and the practical demonstration of high-axial-resolution OCT imaging shows the application of QD-SLDs as a compact OCT light source, which enables the development of a portable OCT system. [ABSTRACT FROM AUTHOR]

Published
2019
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