Dr. Kiyoshi Asakawa Profile

Dr. Kiyoshi Asakawa

Professor/Group Leader at Univ of Tsukuba

SPIE Involvement:

Conference Program Committee | Author

SPIE Journal Paper | 10 February 2021

Selectively excited bimodal interferometer for highly sensitive refractive index sensing

Keito Ebihara, Kiyoshi Asakawa, Hiroaki Suzuki

OE, Vol. 60, Issue 02, 027103, (February 2021) https://doi.org/10.1117/12.10.1117/1.OE.60.2.027103

KEYWORDS: Waveguides, Interferometers, Refractive index, Sensors, Cladding, Glucose, Brain-machine interfaces, Optical engineering, Polymethylmethacrylate, Water

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SPIE Journal Paper | 16 November 2020

Hybrid plasmon waveguide for highly sensitive biosensing

Mohri Kyohsuke, Kiyoshi Asakawa, Hiroaki Suzuki

OE, Vol. 59, Issue 11, 117103, (November 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.11.117103

KEYWORDS: Waveguides, Refractive index, Gold, Water, Biosensing, Plasmons, Surface plasmons, Molecules, Chromium, Optical engineering

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SPIE Journal Paper | 5 January 2017

Silicon nitride directional coupler interferometer for surface sensing

Kyohei Okubo, Ken Uchiyamada, Kiyoshi Asakawa, Hiroaki Suzuki

OE, Vol. 56, Issue 01, 017101, (January 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.1.017101

KEYWORDS: Waveguides, Sensors, Refractive index, Directional couplers, Silicon, Interferometers, Water, Cladding, Polymers, Microfluidics

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Proceedings Article | 22 April 2016 Presentation + Paper

Fabrication and characterization of silicon nitride directional coupler interferometer for sensing aptamer hybridization

K. Okubo, K. Uchiyamada, M. Yokokawa, K. Asakawa, H. Suzuki

Proceedings Volume 9725, 972506 (2016) https://doi.org/10.1117/12.2211899

KEYWORDS: Waveguides, Silicon, Directional couplers, Biosensing, Near field optics, Interferometers, Interferometry, Polymeric sensors, Sensors, Refractive index, Near field, Biosensors, Light wave propagation, Beam propagation method

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Proceedings Article | 23 February 2012 Paper

Phase measurement interferometric microscopy of stacked fishnet metamaterials

T. Matsui, A. Miura, T. Nomura, H. Fujikawa, K. Sato, N. Ikeda, D. Tsuya, M. Ochiai, Y. Sugimoto, H. Miyazaki, M. Ozaki, M. Hangyo, K. Asakawa

Proceedings Volume 8269, 82692P (2012) https://doi.org/10.1117/12.907248

KEYWORDS: Interferometry, Microscopes, Beam splitters, Phase measurement, Metamaterials, Aluminum, Silica, Fringe analysis, Microscopy, Dielectrics

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Proceedings Article | 30 September 2005 Paper

Photonic crystal-based integrated optics for advanced ultra-fast all-optical signal processing

Kiyoshi Asakawa, Yoshimasa Sugimoto

Proceedings Volume 5956, 59560U (2005) https://doi.org/10.1117/12.629087

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Proceedings Article | 17 September 2005 Paper

Ultra-fast and ultra-small photonic crystal/quantum dot all-optical switch for future photonic networks

Hitoshi Nakamura, Yoshimasa Sugimoto, Kyozo Kanamoto, Naoki Ikeda, Yu Tanaka, Yusui Nakamura, Shunsuke Ohkouchi, Kuon Inoue, Hiroshi Ishikawa, Kiyoshi Asakawa

Proceedings Volume 5926, 59260B (2005) https://doi.org/10.1117/12.619928

KEYWORDS: Phase shifts, Surface plasmons, Waveguides, Absorption, Switches, Photonic crystals, Switching, Picosecond phenomena, Indium arsenide, Nonlinear optics

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Proceedings Article | 25 March 2004 Paper

Nanotechnologies of photonic crystals and quantum dots for ultrasmall and ultrafast all-optical switches

Kiyoshi Asakawa, Yoshimasa Sugimoto, H. Nakamura, Naoki Ikeda, Y. Tanaka, Y. Nakamura, S. Ohkouchi, Kozyo Kanamoto, Hiroshi Ishikawa, Y. Watanabe, K. Inoue, H. Sasaki, Koji Ishida

Proceedings Volume 5277, (2004) https://doi.org/10.1117/12.531187

KEYWORDS: Waveguides, Phase shifts, Transmittance, Indium arsenide, Nonlinear optics, Scanning electron microscopy, Photonic integrated circuits, Photography, Gallium arsenide, Photonic crystals

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Proceedings Article | 11 July 2002 Paper

Application of photonic crystal defects in constructing all-optical switches, optical delay lines and low-cross-talk waveguide intersections for ultrashort optical pulses

Sheng Lan, Yoshimasa Sugimoto, Satoshi Nishikawa, Naoki Ikeda, Tao Yang, Kozyo Kanamoto, Hiroshi Ishikawa, Kiyoshi Asakawa

Proceedings Volume 4870, (2002) https://doi.org/10.1117/12.475549

KEYWORDS: Waveguides, Chemical species, Gallium arsenide, Ultrafast phenomena, Switching, Dielectrics, Switches, Dispersion, Molecules, Photonic crystals

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Proceedings Article | 30 October 2001 Paper

Light propagation characteristics of photonic crystal waveguide for miniaturized ultrafast optical-pulse control/delay devices

Yoshimasa Sugimoto, Naoki Ikeda, Niclas Carlsson, Noriko Kawai, Kuon Inoue, Kiyoshi Asakawa

Proceedings Volume 4598, (2001) https://doi.org/10.1117/12.447092

KEYWORDS: Waveguides, Transmittance, Geometrical optics, Quantum dots, Photonic crystals, Light wave propagation, Scanning electron microscopy, Finite-difference time-domain method, Nonlinear optics, Photography

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Photonic crystals (PCs) having two-dimensional (2D) periodicity on a length scale of 320-450 nm were fabricated by electron beam lithography in combination with high- aspect-ratio dry etching. To achieve three-dimensional control of the optical properties, three kinds of dielectric waveguide structures based on AlGaAs heterostructures, that is, semiconductor-clad (SC), air-bridge (AB), and oxide-clad (OC) structures, were investigated. Observation of light propagating through such photonic crystal devices was employed by optical transmission measurements. Clear photonic bandgap effects resulting in 30-dB attentuation of the transmitted light could be observed in the the bandgap regions. The measured results were in good agreement with calculated band-structures and transmission spectra using a Fine-Difference Time-Domain (FDTD) method. Straight, sixty degree-bent and Y-branch defect waveguides (D-WGs) in a 2D- PC slab were fabricated, and the resulting light propagation characteristics were measured by two methods. One was measurement of transmission spectra at wavelengths ranging from 850 to 1100nm. Another was plan-view observation of the optical beam race trace along the waveguide measured with an IR-vidicon camera. Three-dimensional FDTD simulations for the band structure and transmission spectra in the air- bridge slab with and without defect waveguides resulted in the appearance of four defect propagation modes specific to the defect waveguide, between two slab modes for the defect- free PC slab. As an example of the future-promising application of the 2D-PC slab, an ultra-small and ultra-fast optical switching device including quantum dots as large optical non-linearity (%chi^3+S) media is proposed. To demonstrate such a device, recent advancement of a nano- probe assisted processing of arrayed quantum dots is discussed. Achievement of this technology will provide us with a possibility of extremely miniaturized all-optical switching devices in the OTDM optical communication network.

Proceedings Article | 30 July 2001 Paper

AlGaAs-based two-dimensional photonic crystal with defect waveguides for miniaturized ultrafast optical-pulse control/delay devices

Yoshimasa Sugimoto, Naoki Ikeda, Niclas Carlsson, Noriko Kawai, Kuon Inoue, Kiyoshi Asakawa

Proceedings Volume 4532, (2001) https://doi.org/10.1117/12.436011

KEYWORDS: Waveguides, Transmittance, Photonic crystals, Wave propagation, Optical testing, Etching, Photography, Signal attenuation, Radio propagation, Dielectrics

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Proceedings Article | 30 July 2001 Paper

Dry-etching and nanofabrication technology perspective for novel optical devices/components

Kiyoshi Asakawa, Yoshimasa Sugimoto

Proceedings Volume 4532, (2001) https://doi.org/10.1117/12.436023

KEYWORDS: Dry etching, Indium arsenide, Photonic crystals, Etching, Nanotechnology, Quantum dots, Optical communications, Waveguides, Nanofabrication, Semiconductors

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