Maslov Konstantin, Zhang Hao F, Wang Lihong V
Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130.
J Innov Opt Health Sci. 2010 Jan 1;3(4):247-253. doi: 10.1142/S1793545810001118.
The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries. In the focal region, the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface, with a time averaged value equal to zero. This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries. For a free boundary, the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.
光声效应被用于在平面和球面聚焦几何结构中产生短持续时间的准单极声压脉冲。在焦区，压力脉冲的时间分布可以通过前换能器表面附近时间分布的一阶导数来近似，时间平均值为零。这种近似与从具有刚性和自由边界的光声换能器获得的实验结果一致。对于自由边界，焦区内的声压等于跟随介质中光能沉积空间分布的正压与跟随激光脉冲时间分布的负压之和。
