Mode matching for cavity ring-down spectroscopy based upon Brewster's angle prism retroreflectors
US6172823A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 2000 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Jan 20, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/39
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A stable resonator for a ring-down cavity spectroscopy cell having an optic axis. The resonator includes two Brewster's angle retroreflector prisms, each having a plurality of total internal reflection surfaces, with one of the total internal reflection surfaces of at least one of the prisms having a curved surface (either a ground curved surface or a surface curved by the addition, through optically contacting or gluing, of a plano-convex lens to the surface). The prisms are disposed in alignment along the optic axis of the resonator. A spherical mirror or lens, tilted from normal incidence to produce a desired degree of astigmatism, mode matches the radiation into the resonator. One or both of the prisms can be rotated so that light rays enter and leave a surface of the prism nearly at Brewster's angle to the normal of the prism surface. This feature maintains alignment between the prisms and allows the resonator to be tuned.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.