DocumentCode :
2228834
Title :
The quasistatic process in pulsed photothermal detection
Author :
Jian-chun Cheng ; Lei Wu ; Shu-yi Zhang
Author_Institution :
Lab. of Modern Acoust., Nanjing Univ.
fYear :
1993
fDate :
31 Oct-3 Nov 1993
Firstpage :
823
Abstract :
In the pulsed photothermal (PT) displacement detection, the signal displays an apparent quasistatic characteristic, i.e., the signal reaches its maximum point rapidly, and then decreases exponentially. For a quantitative numerical simulation, the quasistatic approximation, i.e., neglecting the inertia term in the thermoelastic displacement equation, is usually considered, which is different from the studies in the laser ultrasonics. In this work, we present a theoretical investigation on the availability of this approximation for a Q-switch laser pulse and a finite thickness of the sample. The results show the signals are characterized by a quasistatic process as the laser pulse rise time is on the order of 0.1 μs, but has a typical dynamic wave behavior as the rise time decreases to the order of 10 ns. The effects of the thermal diffusivity and the sample thickness on the quasistatic characteristic are also discussed in detail
Keywords :
displacement measurement; laser beam effects; measurement by laser beam; photoacoustic effect; photothermal effects; thermal diffusivity; Q-switch laser pulse; dynamic wave behavior; inertia term; laser ultrasonics; pulsed photothermal detection; quasistatic approximation; quasistatic process; thermal diffusivity; thermoelastic displacement equation; Acoustic pulses; Acoustic signal detection; Displays; Equations; Laser theory; Optical pulse shaping; Optical pulses; Optical surface waves; Surface emitting lasers; Thermoelasticity;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Ultrasonics Symposium, 1993. Proceedings., IEEE 1993
Conference_Location :
Baltimore, MD
Print_ISBN :
0-7803-2012-3
Type :
conf
DOI :
10.1109/ULTSYM.1993.339480
Filename :
339480
Link To Document :
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