中文摘要：

建立了激光声测量系统,利用脉冲激光聚焦击穿水介质产生声信号,由水听器将声信号转换成电信号并送入数字存储示波器。给出了光声能量转换效率的计算方法。对光击穿机制下不同激光聚焦位置、不同激光会聚角度的光声能量转换效率进行了实验研究和理论分析。结果表明：激光垂直水面入射时,随着激光聚焦深度的增加,η会出现一次阶跃式变大;水对激光的吸收系数越低,η越大;激光会聚角度的增加能够使η变大;等离子体对激光的吸收系数越高,η越大。

英文摘要：

Experimental system for measurement of laser-induced acoustic signals has been built. The laser is focused into water to produce acoustic signals. A hydrophone is used to receive the laser-induced acoustic signal and transform it into electric signal. The calculation method for laser-acoustic energy conversion efficiency η is given, η in different laser focusing conditions has been investigated in experiment and theory. The results are as follows： η has a step with the increase of laser focusing depth in water;η increases as absorbed energy by water decreases. The increase of focusing angle of laser can improve η. η increases as absorbed energy by plasma increases.