Phase-modulated polarizing interferometer
US4480916A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1982 |
| Grant date | Nov 6, 1984 |
| Priority date | — |
| Expiry date | Jul 6, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interferometer for measuring optical surfaces which is capable of very high sensitivity. A HeNe laser light is converted into a circular polarized beam, spatially filtered and collimated. The light beam is passed through a photoelastic modulator for modulating the relative phase of the two polarization states of the optical field of the beam. The beam is then passed through a ROCHON prism which splits the beam into two orthogonally polarized components. One beam is reflected off the optical surface that is being measured and is recombined with the undeviated beam. The resulting irradiance distribution oscillates in the modulation frequency and the phase of the oscillation is dependent upon the optical path difference between the two beams. The detected interference signal is processed to extract the phase information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.