Algorithm for resolving 2 pi ambiguities in interferometric measurements by use of multiple wavelengths

Citation
Mg. Lofdahl et H. Eriksson, Algorithm for resolving 2 pi ambiguities in interferometric measurements by use of multiple wavelengths, OPT ENG, 40(6), 2001, pp. 984-990
Citations number
6
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Optics & Acoustics
Journal title
OPTICAL ENGINEERING
ISSN journal
00913286 → ACNP
Volume
40
Issue
6
Year of publication
2001
Pages
984 - 990
Database
ISI
SICI code
0091-3286(200106)40:6<984:AFR2PA>2.0.ZU;2-D
Abstract
Measurement of differences in optical path length in monochromatic light wi th any interferometric method is insensitive to errors that are whole numbe rs of waves. If measurements are performed in several wavelengths, this amb iguity can be resolved. We present a general algorithm for finding the corr ect distance post facto, given multiple measurements in different wavelengt hs. Applied to piston measurements of a segmented mirror, the capture range of a wavefront sensor can be extended from +/- half a wave to several wave s. The extended capture range can be calculated and depends on the selectio n of wavelengths used for measurements and the expected accuracy of the met hod used. (C) 2001 society of Photo-Optical Instrumentation Engineers.