Production of Pico and Subpicosecond Optoacoustic Pulses

J. Acoust. Soc. Am. 85, 1560 (1989)https://ireap.umd.edu/10.1121/1.3973591989Journal ArticlePlasma, Accelerator, and Nuclear Physics

A method for generating pico‐ and subpicosecond optoacoustic pulses is discussed. The physical mechanism is based upon the phenomenon of ‘‘electronic expansion’’ (or photostriction) in which the lattice constant of a solid changes upon the creation of electron–hole pairs. Acoustic signals generated by this mechanism would be up to an order of magnitude shorter than those generated by other schemes currently in use. An expression for the acoustic compression expected in this method is derived. It is shown that the nonthermal nature of the phenomenon, in conjunction with the band structure of materials exhibiting gaps between conduction bands, can be exploited to obtain ultrashort optoacoustic pulses that have no thermoelastic components. A comparison of the thermoelastic and nonthermal photostrictive mechanisms is made.