Absolute calibration of optical flats
Abstract
The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.
- Inventors:
- Issue Date:
- Research Org.:
- Univ. of California, Oakland, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1175308
- Patent Number(s):
- 6876456
- Application Number:
- 10/256,322
- Assignee:
- The Regents of the University of California (Oakland, CA)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01B - MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS
G - PHYSICS G01 - MEASURING G01M - TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES
- DOE Contract Number:
- W-7405-ENG-48
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 47 OTHER INSTRUMENTATION
Citation Formats
Sommargren, Gary E. Absolute calibration of optical flats. United States: N. p., 2005.
Web.
Sommargren, Gary E. Absolute calibration of optical flats. United States.
Sommargren, Gary E. Tue .
"Absolute calibration of optical flats". United States. https://www.osti.gov/servlets/purl/1175308.
@article{osti_1175308,
title = {Absolute calibration of optical flats},
author = {Sommargren, Gary E.},
abstractNote = {The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {4}
}