Real-time detection of laser-induced transient gratings and surface acoustic wave pulses with a Michelson interferometer
作者:
Yao-chun Shen,
Peter Hess,
期刊:
Journal of Applied Physics
(AIP Available online 1997)
卷期:
Volume 82,
issue 10
页码: 4758-4762
ISSN:0021-8979
年代: 1997
DOI:10.1063/1.366332
出版商: AIP
数据来源: AIP
摘要:
Laser-induced transient gratings (LITGs) at surfaces of absorbing materials were utilized to generate narrowband surface acoustic waves (SAWs). In these experiments, SAWs were excited thermoelastically by two crossed picosecond laser pulses and detected with an actively stabilized Michelson interferometer by measuring transient surface displacements in the sub-angstrom range in real time. In addition, coherent broadband SAW pulses with frequencies up to 350 MHz were excited by sharply focusing the laser beam with a cylindrical lens system onto the sample surface. The LITG experiments provide an extension of the frequency range achieved with the broadband SAW pulse technique. From the measurements of the dispersive SAW phase velocity for a 650 nm aluminum film on fused silica in the frequency range 10 MHz–1 GHz the density and elastic constants were determined by fitting the experimental data to the exact solution of the wave equations taking into account the boundary conditions. ©1997 American Institute of Physics.
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