激光脉冲波形对液体中热膨胀机制致声特性的影响  

Effects of Laser Pulse Waveform on Characteristic of Acoustic Waves Generated through Thermoelastic Mechanism in Liquid

作　　者：李秋实[1] 倪明[1] 罗洪[1] 胡永明[1] 

机构地区：[1]国防科技大学光电科学与工程学院,长沙410073

出　　处：《半导体光电》2010年第3期478-484,共7页Semiconductor Optoelectronics

摘　　要：首先阐述了激光与液体媒质作用通过热膨胀机制激发平面光声源的理论;分别针对激光脉冲为正弦波形、三角波形和高斯波形的情况,推导了激光脉冲分别在约束界面和自由界面下产生声脉冲的解析解,然后通过仿真得到了激发声波的光声脉冲剖面和时空分布图;并对比分析了正弦波形、三角波形和高斯波形的激光脉冲分别在约束边界和自由边界下激发声波的峰值声压、光声转换效率和波形等特性。The theory of thermoelastic mechanism for generation of a plane acoustic source by a laser pulse in liquid is elaborated firstly. The analytic solutions of the acoustic pulses induced by laser pulses under the condition of rigid interface and free surface are deduced on the assumption that the laser waveform is sinusoid,triangular and Gaussian pulse respectively. And then the photoacoustic pulse sections and temporal and spatial profiles of the acoustic pulses are obtained through emulation. At last,analyzed and compared are the characteristics,including the peak acoustic pressure,the laser-acoustic conversion efficiency,the waveform,etc,of the photoacoustic pulses induced by laser pulses of the three kinds of waveform under the condition of rigid interface and free surface.

关 键 词：激光致声 热膨胀机制 脉冲波形 光声脉冲剖面 峰值声压 光声转换效率 

分 类 号：O426.3[理学—声学]