Visualization of High-speed Phenomena using an Acousto-optic Laser Deflector

Abstract

An acousto-optic laser deflector was used for visualization of high-speed phenomena, such as shock waves and density perturbations accompanying an impulse discharge, or shock waves generated by laser-induced breakdown in air. Using a continuous wave laser as the light source, shadowgraphs of shock waves and density perturbations were obtained at shutter speeds down to 1μs. Results showed that shock waves propagated at a speed of 417 m/s in the case of an impulse discharge, and 485 m/s in the case of laser-induced breakdown. Pre-discharge phenomena such as leaders progressing from the high voltage electrode were also visualized. Compared to conventional high-speed imaging techniques, this method is useful when using a laser light source, since the acousto-optic crystal can accomodate high intensity laser light.