Femtosecond laser-induced pulsed ultrasound source in water

The propagation of intense ultrashort laser pulses in water is affected by group velocity dispersion and nonlinear effects such as self-focusing and multiphoton absorption [1]. For a laser beam with an input peak power exceeding a few MW propagating in water, a filamentation phenomenon can occur producing a self contraction of the beam accompanied by the formation of an extended plasma channel [2]. Recent reports have suggested that femtosecond lasers could be exploited for the development of a remote underwater acoustic source [3, 4].