Method of forming diffraction gratings and optical branching filter elements produced thereby
US4560249A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 1983 |
| Grant date | Dec 24, 1985 |
| Priority date | — |
| Expiry date | Apr 18, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H1/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for making a diffraction grating utilizing a laser source, a beam splitter to split the light from the laser source into two light fluxes, a collimator to convert each light flux into a light flux which is parallel and enlarged in diameter, a mirror to irradiate each light flux on a substrate coated with a photoresist, and a photomask on the photoresist. The use of an intermediate mask and focusing leans enables the formation of a diffraction grating within a limited area. A blazed diffraction grating may be formed by splitting a laser beam into two beams having an increased beam radius, and irradiating a light-sensitive material with the resulting two beams to form an interference fringe. This method is characterized in that in a first exposure the two beams are incident on the light sensitive material through air to form an interference fringe having a clearance width of d, and in a second exposure, the two beams are irradiated on the light sensitive material through a symmetrical transparent member having an isosceles triangular cross section in such a manner that the origin coincides to form an interference fringe having a clearance width of d/2, and furthermore, in th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.