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Phase-shifting point diffraction interferometer

Patent ·
OSTI ID:871971
 [1]
  1. Berkeley, CA
+ Show Author Affiliations
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.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA
DOE Contract Number:
AC03-76SF00098
Assignee:
Regents of University of California (Oakland, CA)
Patent Number(s):
US 5835217
OSTI ID:
871971
Country of Publication:
United States
Language:
English

References (5)

Multichannel phase-shifted interferometer journal January 1984
Liquid-crystal point-diffraction interferometer journal January 1994
Phase-shifting point diffraction interferometer journal January 1996
Progress towards λ/20 extreme ultraviolet interferometry journal November 1995
Theory and Application of Point-Diffraction Interferometers journal January 1975

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