Photoacoustic generation of focused quasi-unipolar pressure pulses
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.
Additional Information© 2010 World Scientific Publishing. This project was sponsored in part by National Institutes of Health Grant Nos. R01 EB000712 and R01 NS46214 (BRP). The authors express special thanks to Mr. Mario Pineda from Polytech, Inc.
Accepted Version - nihms254119.pdf