Light wave diffraction device
US6219478A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1999 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Jan 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/141
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Light wave diffraction device formed of a dielectric layer (4), a reflecting structure (12) arranged on one lower face (10) of said layer, and a diffraction grating (8) arranged on one face (6) of said layer. The height (H) of the layer is selected so as to substantially satisfy the resonance condition for a leaky mode in said layer for at least one given incident wave having a wavelength .lambda. and a determined angle of incidence. Next, the diffraction grating has a spatial period selected so that the incident wave is diffracted essentially along the first negative diffraction order and at an angle of diffraction different to the angle of incidence (outside the Littrow condition). In particular, the invention provides that either the angle of incidence, or the angle of diffraction is high, i.e. relatively close to 90.degree. from the direction perpendicular to the diffraction grating. This diffraction device allows a very high diffraction efficiency, of up to 100%, to be obtained, even when the incident wave is grazing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.