Fluorescent photography of droplets in a spray using a Q-switched laser as a light source

Abstract

A method of using a Q-switched laser as a light source for photographing droplets in a spray is described. A fluorescent dye in the liquid being sprayed was excited by the second harmonic of ruby light at 3471 A. Droplets as small as 10 μm, travelling with velocities as high as 50 m sec-1, were successfully photographed. A dynamic size calibration showed that reliable drop size information could be obtained from the spray photographs.