High accuracy differential plane mirror interferometer
US4950078A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 8, 1988 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Dec 8, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A differential plane mirror interferometer system comprises a laser source (10) which emits an input beam (12) having two linear orthogonally polarized components, which may or may not be of the same optical frequency. A birefringent optical element (64) converts the input beam components (20,21) into two separated, parallel, orthogonally polarized beams (22,23). The birefringent element (64) together with a first quarter-wave phase retardation plate (66), a second quarter-wave phase retardation plate (62) with a pair of holes, and a retroreflector (60) with a pair of holes aligned with the holes in the second quarter-wave phase retardation plate (62), causes each of the separated, parallel, orthogonally polarized beams to be reflected twice by one of two plane mirrors (68,70), namely a first plane mirror (68) or a second plane mirror (70), respectively, to produce two separated, parallel, orthogonally polarized output beams (54, 55). The birefringent optical element (64) converts the two separated, parallel, orthogonally polarized outbeams (54, 55) into a single output beam (80) in which the phase difference between the two polarization components of the single output beam (80) is…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.