Experimental and theoretical analysis of transient grating generation and detection of acoustic waveguide modes in ultrathin solids
作者:
Jeffrey S. Meth,
C. D. Marshall,
M. D. Fayer,
期刊:
Journal of Applied Physics
(AIP Available online 1990)
卷期:
Volume 67,
issue 7
页码: 3362-3377
ISSN:0021-8979
年代: 1990
DOI:10.1063/1.345380
出版商: AIP
数据来源: AIP
摘要:
A full theoretical analysis of and experimental evidence for the optical generation and detection of acoustic waveguide modes (Lamb waves) in ultrathin solids using the transient grating (TG) technique is presented. The driving force due to the TG excitation is derived for a free, isotropic plate. In contrast to a bulk isotropic material in which a single wave is excited, the TG excites a number of modes with a variety of frequencies but with the same tangential component of the wavevector. The frequencies beat, resulting in a complex time‐dependent signal. Experimental results are presented for anthracene sublimation flakes. In addition to discussing the general features of Lamb wave generation, we also discuss the effects of mounting the crystal on a substrate, of varying the fringe spacing, of resonant probing, and of polarized detection. The nature of Lamb waves in anisotropic materials is illustrated, and the extent to which the isotropic theory can be applied to anisotropic systems is discussed.
点击下载:
PDF
(2047KB)
返 回