Focusing and cumulation of optothermoacoustic shock pulses by a concave surface heated by a laser pulse

A study was made of cumulation of optothermoacoustic pulses in the course of interaction of light with a concave surface of an absorbing medium. Strong ejection of a liquid from the focus was observed and measurements were made of the amplification of shock pulses on approach of a detecting sensor to the focus. An analysis was made of various types of active mirrors capable of simultaneous generation and focusing of shock pulses. Possible mechanisms of generation of sound by an absorbing layer were considered, including heating, boiling, pulsed sublimation, exothermal combustion, etc. Potential applications were considered.