早在电话刚刚问世的十九世纪末,电话的发明者贝尔就曾大胆设想:总有一天,人们可以通过从窗户玻璃上反射回来的太阳光线,在远处听到窗户里人们的讲话。现在,人们已经能够把一束激光打到窗户上,从接受反射回来的光线中得到屋里的讲话声。本文叙述利用激光束遥测微弱声信号的原理和应用。超外差式激光微振检测的原理如图1所示,频率为 f_0的激光束照射到以速度 u=u_0cosΩt 振动的物体表面,受到振动的调制,得到瞬时频率为(f_0+2f_0 _c~v_0cosΩf)的反射光,即信号光束;另外,来自同一激光源的另一束激光经声光频移获得频率为 f_0+f_A 的一级衍射光,即参考光束。将两束激光在光检测器 As early as the end of the nineteenth century when the telephone was first introduced, Bell, the inventor of the telephone, dared to imagine that one day people could hear the people in the distance speaking through the sun’s rays reflected from the window glass. Now people are able to hit a window with a laser beam and get their voice from the light that is reflected back. This article describes the principle and application of using telemetry to detect weak acoustic signals with laser beams. Super heterodyne laser micro-vibration detection principle shown in Figure 1, the frequency of f_0 laser beam irradiated to the speed of u = u_0cosΩt vibration of the object surface, subject to vibration modulation, the instantaneous frequency (f_0 + 2f_0_c ~ v_0cosΩf ), Ie, the signal beam. In addition, another laser beam from the same laser source is acousto-optic frequency shifted to obtain a first order diffracted beam of frequency f_0 + f_A, ie, a reference beam. Two beams of laser light detector