不同盐度海水的光击穿声辐射特性研究

Study of optical breakdown laser-generated sound in salt water

强激光聚焦于水下时,通过光击穿机制辐射强声波信号。水体介质的盐度不同,在同等的激光参数、光学系统条件下,光击穿辐射的声波在强度、脉冲波形、频谱特征上具有一定的差异性。为研究水介质盐度对激光击穿形成的空泡辐射声波的影响,构建了激光声测量系统,实验研究了不同水体盐度参数对光击穿辐射声信号的影响。结论:激光击穿水介质伴随空泡脉动、声信号辐射效应;激光声信号脉冲宽度与水体盐度无关;空泡尺寸和激光声信号强度与激光脉冲能量成正比关系;水体盐度与激光声信号的强度早非线性变化关系。研究结果有助于激光声在海洋中的应用。

The laser - based transmitter provides a versatile method for generating underwater sound. The water salinity relates to the acoustic waveform in the condition of the same parameter of laser and optical system. The experimental investigation of the shock wave after optical breakdown in water with Nd： YAG laser pulses is formed. The pressure acoustic signal generated by laser - induced is detected with the high - frequency transducer. The laser - induced cavitation bubble expansion and collapse were recorded with high - speed video. In general, the shock wave and cavitation bubble begin after optical breakdown in water with Nd： YAG laser pulses. The laser induced bubble radius and power acoustic density make a linear relation with the laser energy directly. The power acoustic density makes a non - linear relation with the water salinity.