A Transient Experiment Using a Multiple-Pulse Laser Light Source.

摘要

A technique of passively Q-switching a dye laser is applied to photograph transient development of an unsteady, underexpanded jet. In this technique, a bleachable absorber was used to generate multiple laser pulses which backlighted a Mach-Zehnder optical interferometer used to observe the jet flow;instantaneous images of the laser-illuminated event were swept onto a fixed film drum by a mirror rotating at approximately 75,000RPM for a film writing speed of approximately 16mm/microsec. The success ratio was achieved despite the fact that control of pulse separation,number of pulses,duration of lasing action,and pulse-to-pulse intensity was not precise. There was more success with the passive technique than with an electronic,high voltage technique--described in the report--for multiple Q-switching of a Pockels cell.