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US 6,788,422 B2Granted
Method and apparatus for using quasi-stable light sources in interferometry applications
AssigneeZygo Corporation
InventorLeslie L. Deck
Life of this patent
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Abstract
Techniques for performing phase-shifting interferometry are disclosed.
Claims23
An interferometry method, comprising:
- positioning a measurement surface within an interferometer that derives measurement and reference wavefronts from a tunable coherent light source that exhibits mode-instabilities within a range of wavelengths;
- measuring an interference signal at each of multiple positions of a series of optical interference patterns produced by the interferometer, wherein each pattern in the series corresponds to one of multiple wavelengths in the wavelength range of the source;
- and
- identifying whether a portion of the interference signals is corrupted by a mode-instability in the light source.
1 more element
An interferometric system, comprising:
- an interferometer comprising a mount to position a measurement object relative a reference surface and configured to receive light from a tunable light source and generate an optical interference pattern comprising a superposition of a measurement wavefront of a measurement beam reflected from a surface of the measurement object and a reference wavefront of a reference beam reflected from the reference surface;
- a detector configured to record an interference signal at multiple locations of the optical interference pattern generated by the interferometer;
- and
- a system controller connected to the light source and the detector and which during operation causes the light source to generate light at each of multiple wavelengths, causes the detector to record the interference signals for each of the multiple wavelengths, and implements an algorithm to identify whether a portion of the interference signals is corrupted by a mode-instability in the light source.
1 more element
Dependencies are inferred from the claim text.