Theory of Second-Harmonic Generation of a Nonlinear Photoacoustic Response Of Two-Layer Samples With Gas–Microphone Signal Recording
Salikhov T.H. Khodjaev Y.P. Makhmalatif A. Sharifov D.M.
January 2025Springer
Radiophysics and Quantum Electronics
2025#67Issue 8614 - 626 pp.
We have formulated a mathematical model for a nonlinear photoacoustic (PA) response of two-layer samples. The features of second-harmonic (SH) generation of a nonlinear PA signal by these samples are studied in detail. Simple expressions for the amplitude of this signal, which describe its dependence on the modulation frequency of the incident beam, as well as on the thermal coefficients of thermophysical parameters and emissivity of the samples, are obtained for the most interesting cases. It was found that only for the case where the first layer is highly absorbing and both layers are thermally thick the frequency dependence of the SH amplitude of the PA signal has the form ω−5/2 and is described by the function ω−3/2 in all other cases. Only for nontransparent layers does the thermal coefficient of emissivity of the corresponding layer contribute to the amplitude of this signal.
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Tajik National University, Dushanbe, Tajikistan
Astana IT University, Astana, Kazakhstan
Tajik National University
Astana IT University
10 лет помогаем публиковать статьи Международный издатель
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