Interferometry system having reduced cyclic errors
US6181420A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 6, 1998 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | Oct 6, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention features a phase measurement system for minimizing cyclic errors in a relative phase between exit reference and measurement beams emerging from an interferometer. The phase measurement system includes: a first optical processing channel including a first polarizer and a first detector, wherein during operation a first portion of the exit reference and measurement beams pass through the first polarizer to produce a first mixed beam and wherein the first detector measures an intensity of the first mixed beam; a second optical processing channel including a quarter wave retarder, a second polarizer, and a second detector, wherein during operation a second portion of the exit reference and measurement beams passes through the retarder and then the second polarizer to produce a second mixed beam and wherein the second detector measures an intensity of the second mixed beam; and a signal processor which during operation receives signals from the first and second detectors indicative of the intensities of the first and second mixed beams and processes the signals to determine, and minimize cyclic errors in, the relative phase between the exit reference and measurement beams.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.