An interferogram produced by wide-aperture interferometers is studied both theoretically and experimentally. The fringe spacing is shown to increase nonlinearly with the numerical aperture and the fringe envelope to become narrower as the numerical aperture is increased. Phase measurements with wide-aperture interferometers therefore require calibration, and the phase can be measured only over a limited range. A calibration is given for accurate phase measurements, and the range over which the phase can be measured is calculated. Experimental measurements are presented and compared with theory.
© 2000 Optical Society of America
[Optical Society of America ]
(120.2830) Instrumentation, measurement, and metrology : Height measurements
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
(180.3170) Microscopy : Interference microscopy
Arnaud Dubois, Juliette Selb, Laurent Vabre, and Albert-Claude Boccara, "Phase Measurements With Wide-Aperture Interferometers," Appl. Opt. 39, 2326-2331 (2000)