Photoacoustic generation of focused ultrasonic pulses with predefined temporal profiles including quasi-unipolar pressure pulses
One of the applications of the photoacoustic effect in biomedical research is generation of ultra-short acoustic pressure pulses in tissue. An acoustic wave is generated directly in tissue or in an acoustically well coupled immersion liquid, thus avoiding mechanical resonances of the piezoelectric ultrasonic transducer. Although laser generation of the unipolar pressure pulses has been proposed and used before, little attention was paid to the change of the temporal shape of the pulse when it propagates from a transducer. Here we derive simple mathematical solution which helps to predict the pulse shape in the focal region of the transducer and to experimentally verify theoretical calculations showing generation of short quasi-unipolar pressure pulses.
Additional Information© 2008 Society of Photo-Optical Instrumentation Engineers (SPIE). This project was sponsored in part by National Institutes of Health Grant Nos. R01 CA106728 and R01 NS46214 (BRP). The authors express special thanks to Mr. Mario Pineda from Polytech, Inc., who made it possible for us to use a laser virbrometer, without which the experimental part of this work could not be performed.
Published - 68560C.pdf