A new method for simple and sensitive detection of photothermal strain caused by laser irradiation of plastic plates has been proposed. In-plane strain of the surface is detected directly by optoelectronic detection of speckle displacements at two symmetrical positions about a probe beam. The initial bending of the plate owing to the temperature gradient along the plate thickness is measured and shows good agreement with one-dimensional calculations.
© 1997 Optical Society of America
Original Manuscript: June 4, 1996
Revised Manuscript: September 11, 1996
Published: May 1, 1997
Ichirou Yamaguchi, Dobromir Palazov, Eisuke Natori, and Jun-ichi Kato, "Detection of photothermal effect by laser speckle strain gauge," Appl. Opt. 36, 2940-2943 (1997)