Measurements of in-plane displacements of rough surfaces show strong influence of the sample structure on the registered signal. Rapid signal amplitude changes as function of sample position for various illumination angles introduce certain indeterminacy and can decrease the accuracy of the measurement system. To find measurements limits the experimental study of the flight diffracted on rough surfaces was performed. Experimental set-up with various illumination systems was built. To compensate environment influences the reference signal was applied. The notion of the probability of the heterodyne signal was introduced and determined for various illumination angles and surface treatments. A modification of heterodyne interferometry system for in-plane displacement measurements was proposed and discussed.

Date Published: 30 June 1998
PDF: 11 pages
Proc. SPIE 3478, Laser Interferometry IX: Techniques and Analysis, (30 June 1998); doi: 10.1117/12.312942

Published in SPIE Proceedings Vol. 3478:
Laser Interferometry IX: Techniques and Analysis
Malgorzata Kujawinska; Gordon M. Brown; Mitsuo Takeda, Editor(s)