液体中光声热弹光穿透效应的研究

Study on Effect of Optical Penetration on the Thermoelastic Ultrasound Generated by Laser in Liquid

从光声热弹性的基本方程出发 ,在理论和实验上研究了液体在激光直接照射下产生超声波时 ,光穿透深度对声源的影响。在二维情况下 ,忽略热扩散效应 ,利用汉克积分变换法和最陡下降法解热扩散方程和波动方程 ,得出位移的解析表达式。讨论了光穿透深度对声源指向性的影响 ,并用数值计算方法和绘图软件画出光穿透深度对声源指向性影响的理论曲线图。最后 ,利用实验验证了理论结果。

The sound source which is generated by laser in liquid is studied theoretically and experimentally on the basis of the thermoelastic equation. The influence of the optical penetration depth on the ultrasonic source is considered. In two-dimensional model, the thermal diffusion effect is neglected. From the thermal diffusion equation and wave equation, the general expression of displacement is given. The influence of the optical penetration depth on the sound directivity is analyzed. The theoretical curve of the sound directivity versus the optical penetration depth is drawn. In the end, the experiments testify the theoretical results.