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Your search keyword '"Yamada, Takatoshi"' showing total 28 results
Start Over Author "Yamada, Takatoshi" Publisher iop publishing
28 results on '"Yamada, Takatoshi"'

4. Spectroscopic ellipsometry of amorphous Se superlattices

Author

John, Joshua D, primary, Okano, Shun, additional, Sharma, Apoorva, additional, Nishimoto, Satoru, additional, Miyachi, Noritoshi, additional, Enomoto, Kunitaka, additional, Ochiai, Jun, additional, Saito, Ichitaro, additional, Salvan, Georgeta, additional, Masuzawa, Tomoaki, additional, Yamada, Takatoshi, additional, Chua, Daniel H C, additional, Zahn, Dietrich R T, additional, and Okano, Ken, additional

Published
2021
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8. Fabrication of a Solid Immersion Mirror and Its Optical Evaluation

Author

Kenjiro Watanabe, Hiroyuki Ueda, Yamada Takatoshi, Takeshi Mizuno, Hiroyuki Sakakibara, and Kawakita Satoshi

Subjects
Fabrication, Materials science, Physics and Astronomy (miscellaneous), business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, General Engineering, Process (computing), Physics::Optics, General Physics and Astronomy, Numerical aperture, Root mean square, Optics, Slider, Immersion (virtual reality), Adaptive optics, business, Optical disc
Abstract

We report the optical design of a solid immersion mirror (SIM) incorporated with a flying slider – called a SIM slider – for a near-field recording (NFR) system, its fabrication process, and optical evaluation. To achieve diffraction-limited performance ~λ/14 (rms), a two-step glass-molding process was employed to fabricate the SIM. The numerical aperture of the SIM slider was 1.29. The rms value of the total wavefront aberration was 0.0679λ. The fabricated SIM slider achieves the optical performance estimated by calculation with the fabrication errors considered, and even diffraction-limited performance. However, an rms value of 0.035λ–0.04λ for the total wavefront aberration is generally assigned for condensing optics for practical use because not only condensing optics but also other optical elements are involved in a practical optical disc system. Therefore, the aberration caused by the fabrication errors in the molding process should be reduced to at least 59% of the present level, if the SIM is to be applied to a practical NFR system.

Published
2002
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28. Improvement of multilayer graphene synthesis on copper substrate by microwave plasma process using helium at low temperatures.

Author

Kato, Ryuichi, Tsugawa, Kazuo, Yamada, Takatoshi, Ishihara, Masatou, and Hasegawa, Masataka

Abstract

A pretreatment method for copper foil substrates for graphene synthesis with microwave plasma has been developed using a helium and hydrogen gas mixture. Contaminants on the surface of the substrate, particularly copper oxides, were effectively removed by this method, which was confirmed by X-ray photoelectron spectroscopy (XPS). Graphene was grown by microwave-plasma-assisted chemical vapor deposition (MWCVD) subsequent to the pretreatment of the substrate in the same apparatus. Using the hydrogen and helium gas mixtures as the diluent gas for methane, the contamination in the deposited graphene by undesirable impurities from the ambient in the reaction apparatus, particularly silicon etched from the quartz window by microwave plasma, was successfully suppressed. The multilayer graphene films synthesized at low temperatures on the pretreated copper foil substrates exhibited higher crystallinity, as shown in transmission electron microscopy (TEM) images and Raman scattering spectra, than those on the untreated substrates. [ABSTRACT FROM AUTHOR]

Published
2014
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