Abstract

We are using pulsed holography to record the debris cloud resulting from the impact of 4 km/s projectiles with plates; this is four times faster than any previous results. Our raison d'etre is 3-D hydrocode verification. We are actually recording holographic shadowgrams of these ~50 mm diameter debris clouds. The object that is holographically recorded is a translucent screen located behind the cloud. Our double-YAG laser with a 5-ns pulse freezes shadows of the debris caught between the screen and the film. During the laser pulse, the particles move about 20 µm, which causes a slight blurring. The laser and the timing system are operational, and we have recorded a 4.2 km/s event. We are now improving the wave-front quality of the reference and reconstruction beams, which will increase our resolution. We are also studying methods of reducing speckle in the image and what the shadows of 3-dimensional particles look like. Finally, we are reviewing automated particle identification and cataloging schemes.

© 1992 Optical Society of America