In situ optoacoustic measurement of the pointing stability of femtosecond laser beams

A new method for the in situ acoustic measurement of the beam pointing stability (BPS) of powerful pulsed lasers is tested. A broadband (~6 MHz) piezoelectric transducer placed a few millimeters from the laser spark produces an electric pulse. We show that variation in time of the position of this pulse can be used to assess the BPS down to 1 µrad in a few hundred laser shots. The estimated value coincides well with the BPS estimated using standard measurement in the far field.