Linear and angular displacement measuring interferometer
US4881815A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 8, 1988 |
| Grant date | Nov 21, 1989 |
| Priority date | — |
| Expiry date | Jul 8, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A single interferomter system capable of measuring accurately linear displacement and angular displacement simultaneously of a movable plane mirror (90) comprises a source (10) of a frequency stabilized input beam (12), a polarization beamsplitter (80), two quarter-wave plates (88, 108), a mirror (89), and a retroreflector (81), to reflect one polarization component of the input beam (12) twice from the movable mirror (90) to produce a first output beam and to reflect the other polarization component of the input beam (12) twice from the stationary mirror (89) to produce a second output beam. The beamsplitter (80) recombines the output beams into a third output beam having two orthogonally polarized components related to the linear displacement of the movable mirror (90) at the first position. The third output beam is divided into a fourth output beam and a fifth beam parallel to, spatially displaced from, and traveling in the same direction as the input beam (12) and has its polarization components rotated by 90 degrees from the third output beam. The interference between the components of the fourth beam is detected by photodetector (94) and the phase change is extracted from the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.