A Transient Experiment Using a Multiple-Pulse Laser Light Source
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
Pagination or Media Count:
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 75,000 RPM for a film writing speed of approximately 16mmmicrosec. 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.
- Lasers and Masers
- Fluid Mechanics