Wavelength shifting in spectrally-controlled interferometry
US10816408B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2018 |
| Grant date | Oct 27, 2020 |
| Priority date | — |
| Expiry date | Jul 28, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2009/0253
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A light source capable of spectral modulation is modulated conventionally to produce a correlogram at the test surface position of an SCI interferometer. The mean wavelength of the light source is changed to obtain multiple corresponding phase-shifted correlograms that can be processed by applying conventional multiple-wavelength interferometric analysis to determine physical attributes of the test surface. One simple way to achieve this result is by splitting the light beam produced by the source into at least three simultaneous beams passed through filters with corresponding different mean-wavelength transmission bands. Because the correlograms are produced simultaneously, they can be used to practice instantaneous phase-shifting interferometry using conventional analysis algorithms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.