Differential plane mirror interferometer having beamsplitter/beam folder assembly
US4802764A · kind A · utility
Inventors
Key dates
| Filing date | Aug 28, 1987 |
| Grant date | Feb 7, 1989 |
| Priority date | — |
| Expiry date | Aug 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A differential plane mirror interferometer comprises a source (10) which emits a light beam containing two orthogonally polarized components of different frequencies; a source of a stabilized electrical reference signal (11) of a frequency corresponding to a difference frequency between the two components of the light beam; a beamsplitter/beam folder assembly (16, 16A) for converting the input beam into two separated, parallel, orthogonally polarized beams; a half-wave retardation plate (29A, 29) located in one of the separated beams to produce two separated parallel beams with the same polarization; means including a polarizing beamsplitter (44), for causing each of the separated parallel beams with the same polarization to be reflected twice by one of two plane mirrors (71, 70) to produce two parallel output beams with the same polarization; a half-wave retardation plate (29B, 29) located in one of the separated parallel output beams, with the beamsplitter/beam folder assembly (16, 16B) converting the two separated parallel orthogonally polarized output beams into a single output beam in which the phase difference between the two frequency components of the single output beam is …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.