为了了解激光声在液体中的传输特性, 理论分析了激光声的传输特性, 并采用高速照相机、光纤MEMS水听器对激光声进行了实验研究, 利用小波变换对采集的不同位置上的激光声信号各级频谱特性进行了分析。结果表明: 激光声属于一种脉动球源, 激光声信号传输过程中幅度与距离成反比关系; 激光声的分析频带内存在明显的优势频率, 峰值频率稳定在3.1 kHz, 带宽稳定在3 kHz; 低频信号的能量占总能量的70%以上, 高频部分主要是噪声; 从功率谱波形分析看, 低频信号的强度幅值随时间、距离变化衰减较慢, 而高频噪声随时间、距离变换衰减较快。

In order to understand the transmission properties of laser-induced acoustic in liquid, the transmission properties of laser-induced acoustic were analyzed theoretically, and the experimental research on the laser-induced acoustic was carried out by using high speed camera and fiber MEMS hydrophone. Wavelet transform was used to analyze the spectrum characteristics of the laser-induced acoustic signals at different locations. The results show that the laser-induced acoustic is a pulsating source, amplitude and distance are inversely proportional in the process of laser acoustic signal transmission; laser acoustic analysis of band memory has obvious dominant frequency, with peak frequency stability of 3.1 kHz and bandwidth stability of 3 kHz; low frequency signal energy accounted for more than 70% of the total energy, high frequency part is mainly noise; from the power spectrum waveform analysis, low frequency signal amplitude with time and distance attenuation is slower, and high frequency noise with time and distance transform decays faster.