Utilisation d’une source laser pulsée à haute energie comme source acoustique large bande en milieu liquid: Source acoustique générée par un laser pulsé intense

In this work the non-linear opto-acoustic problem which consists in generating an acoustic signal in water from an intense ultra short laser pulse has been studied. The acoustic source obtained could be related to the phenomenon of filamentation which produces a contraction of the initial beam accompanied by the formation of plasma. Relatively recent work has shown that lasers of this type could be used to produce remote acoustic sources with interesting applications to underwater acoustics. The spectrum of the sound source obtained was investigated and its directivity pattern in both planes (plane of the filament and plane perpendicular to the filament) was measured. The sound level of the source as a function of energy,duration,and wavelength of the laser pulse was also measured.