Pulsed Laser Diode for Use as a Light Source for Short-Exposure, High-Frame-Rate Flow Visualization

Abstract

A pulsed laser diode (PLD) is demonstrated as a practical light source for high-speed digital schlieren and shearing-interferometric cinematogrpahy. Frame rates of greater than 300k fps with exposure times on the order of 10 ns have been achieved with an inexpensive and user-friendly setup. The light source has primarily been used in our laboratory to study nonsteady phenomena in high-speed gas flows. Examples are presented to illustrate the usefulness of the PLD as a light source with characteristics of a narrow band of wavelength, short exposure time, high frame-rate, and long pulse train duration.