Reflection type diffraction grating
US6839173B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2001 |
| Grant date | Jan 4, 2005 |
| Priority date | — |
| Expiry date | Sep 17, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/1861
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A reflection type diffraction grating according to the present invention has a structure in which a metal film as a first layer with reflectance not lower than 30% with respect to the wavelength of incident light and a transparent dielectric film as a second layer are laminated successively on the surface of the reflection type diffraction grating. With respect to the wavelength of incident light, the metal film has a refractive index selected to be not higher than 1.5 and an extinction coefficient selected to be not smaller than 6.0. The transparent dielectric film has a refractive index selected to be in a range of from 1.30 to 1.46, both inclusively, with respect to the wavelength of incident light and has an optical film thickness selected to be in a range of from 0.20λ to 0.38λ, both inclusively, when λ is the wavelength of incident light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.