Abstract

Most photoacoustic experiments are concerned with the generation and detection of small amplitude sound waves after optical absorption. In this paper, we study the opposite case: generation and detection of large amplitude shock waves by a pulsed laser. The generation is achieved by taking advantage of the efficient ionization of metal vapors by resonant¹ or quasi-resonant^2,3 laser beams. In general, photoacoustic generation can be due to various causes; for example: collisional deexcitation resulting in thermal expansion, photodissociation, gas evolution, photoionization and optical breakdown, and so on. For the present case of optical breakdown in a vapor, the photoacoustic generation efficiency can be especially high, because ionization causes an increase in the total particle density, and also the electrons produced usually have large kinetic energies. Hence, large-amplitude shock waves can be generated by laser-induced breakdown.

© 1981 Optical Society of America