Achromatic self-referencing interferometer
US5305074A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 17, 1992 |
| Grant date | Apr 19, 1994 |
| Priority date | — |
| Expiry date | Jul 17, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2009/002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A self-referencing Mach-Zehnder interferometer for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ("first" interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mount…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.