Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300 USA.
Appl Spectrosc. 2013 Oct;67(10):1111-6. doi: 10.1366/13-07068.
A theoretical model for a time-resolved photothermal mirror technique using pulsed-laser excitation was developed for low absorption samples. Analytical solutions to the temperature and thermoelastic deformation equations are found for three characteristic pulse profiles and are compared to finite element analysis methods results for finite samples. An analytical expression for the intensity of the center of a continuous probe laser at the detector plane is derived using the Fresnel diffraction theory, which allows modeling of experimental results. Experiments are performed in optical glasses, and the models are fitted to the data. The parameters of the fit are in good agreement with previous literature data for absorption, thermal diffusion, and thermal expansion of the materials tested. The combined modeling and experimental techniques are shown to be useful for quantitative determination of the physical properties of low absorption homogeneous linear elastic material samples.
针对低吸收样品，我们开发了一种使用脉冲激光激发的时间分辨光热反射镜技术的理论模型。针对三种典型的脉冲轮廓，找到了温度和热弹性变形方程的解析解，并将其与有限样本的有限元分析方法的结果进行了比较。利用菲涅耳衍射理论推导出了在探测器平面上连续探测激光中心强度的解析表达式，该表达式允许对实验结果进行建模。在光学玻璃中进行了实验，并将模型拟合到数据上。拟合的参数与之前文献中测试材料的吸收、热扩散和热膨胀的参数吻合较好。综合建模和实验技术可用于定量确定低吸收各向同性线性弹性材料样品的物理性能。
