Sharp Kabushiki Kaisha Corporation

Sharp Corporation

Toshihiko Takano

Yoshio Inoue

Yoshio Okada

Shigeo Harada

Kouzaburo Yano

Terutaka Tokumaru

Yukiko Kobayashi

A metal surface plasmon is excited in a multi-layered film composed of thin metal films and a thin dielectric film, by light having a propagation constant larger than that of the incident light emitted from an optical component such as a prism. Due to an extremely strong alternating electric field produced by the electric field enhancement effect of the metal surface plasmon, a harmonic is generated from a nonlinear optical crystal.

Optical harmonic generator

An optical harmonic generator for obtaining a harmonic with a wavelength which is an integral measure of the wavelength of incident light by the use of a nonlinear optical effect is provided which is used, for example, to obtain a laser beam having a shorter wavelength. The optical harmonic generator is formed by laminating a dielectric, a metal thin film, and a nonlinear thin film waveguide. A very strong alternating electric field, produced by the electric field enhancement effect of a metal surface plasmon excited by the metal thin film, is applied near the interface between the nonlinear thin film waveguide and the metal thin film, and a harmonic is generated from the nonlinear thin film waveguide by the alternating electric field. By selecting the film thickness of the metal thin film and the depth of the nonlinear thin film waveguide, phase matching between the incident light and the generated harmonic is achieved.

A reversible temperature indicating material which is chemically stable, is not harmful and can be produced relatively inexpensively contains as principal component a polycrystalline bismuth-chromium oxide substance produced by firing a mixture with 50-86 molar % of bismuth-containing compounds and 50-14 molar % of chromium-containing compounds.

Growing community of inventors

Kashiwa, Japan

Toshihiko Takano