Measurement of Shock Waves Using an Acousto-Optic Laser Deflector

Abstract

Laser interference fringe patterns and shadowgraphs were obtained with a minimum exposure time of 200 ns using an acousto-optic laser deflector. Experimental results showed that this method has sufficient spatial and temporal resolution to image the wavefront of shock waves generated by laser-induced breakdown in air. The shock waves propagated at a speed of over 10³ m/s immediately after breakdown, and at a nearly constant speed of about 510 m/s for 3-9 μs after breakdown. The width of the wavefront of the shock wave was measured to be 0.17 mm, and the neutral density variation at the wavefront was estimated to be 9×10²⁴ m^-3.