Determination of thermoelastic material properties by differential heterodyne detection of impulsive stimulated thermal scattering

Abstract

The underlying working principle of detecting impulsive stimulated scattering signals in a differential configuration of heterodyne diffraction detection is unraveled by involving optical scattering theory. The feasibility of the method for the thermoelastic characterization of coating-substrate systems is demonstrated on the basis of simulated data containing typical levels of noise. Besides the classical analysis of the photoacoustic part of the signals, which involves fitting surface acoustic wave dispersion curves, the photothermal part of the signals is analyzed by introducing thermal wave dispersion curves to represent and interpret their grating wavelength dependence. The intrinsic possibilities and limitations of both inverse problems are quantified by making use of least and most squares analysis.

Characterization of Texture Evolution during Recrystallization by Laser-Induced Transient Thermal Grating Method

“…An ISS setup [17][18][19] was used, shown in Figure 2. SAWs are excited by an impulsively stimulated thermal grating, which are generated by optical absorption of two crossing pulsed laser beams (pulse width: 10 ps, wavelength: 1064 nm, repetition rate: 1 kHz, energy: 30 µJ/ pulse) on the surface of sample.…”

“…For example, large and negative C 12 4 cause transverse earring, while large and positive C 13 4 cause rolling and transverse earring effect [1,10]. However, few researchers have analyzed the influence of each texture component on the SAW dispersion during recrystallization; in addition, there is also a lack of online texture detection theoretical model based on laser ultrasound.In this work, one of the pulsed laser ultrasonic techniques, i.e., the transient thermal grating technique [17][18][19], has been known as Impulsive Stimulated Scattering (ISS), which is used to study texture evolution during recrystallization processing of cold rolled interstitial free (IF) steel sheets. The anisotropies of angular dispersions of SAW velocities were obtained and the effect of the {100}, {110} and {111} textures of polycrystalline materials were analyzed.…”

“…In this work, one of the pulsed laser ultrasonic techniques, i.e., the transient thermal grating technique [17][18][19], has been known as Impulsive Stimulated Scattering (ISS), which is used to study texture evolution during recrystallization processing of cold rolled interstitial free (IF) steel sheets. The anisotropies of angular dispersions of SAW velocities were obtained and the effect of the {100}, {110} and {111} textures of polycrystalline materials were analyzed.…”

Determination of elastic properties of a MnO2 coating by surface acoustic wave velocity dispersion analysis

“…For a more detailed description, the reader is referred to Ref. 26. A 10 ps pulsed laser beam (1047 nm) was focused, by a cylindrical lens, into a horizontal line onto a surface relief square wave grating.…”

Thermal diffusivity determination using heterodyne phase insensitive transient grating spectroscopy

“…Optically heterodyne amplified transient grating spectroscopy (TGS) measurements are a powerful tool used in the study of surface thermal transport [1], elastic mechanical performance [2], film properties [3][4][5][6], and a variety of other dynamic processes [7][8][9]. TGS has proven a particularly useful tool for studying the properties of heterostructures [10] as well as short-wavelength, nonballistic heat transport in semiconductors [11].…”