Phase-shifting point diffraction interferometer
US5835217A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 28, 1997 |
| Grant date | Nov 10, 1998 |
| Priority date | — |
| Expiry date | Feb 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/706
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.