A frequency-doubled Nd:YAG laser with an unstable resonator is explored for its capabilities as a coherent light source for, holographicmeasurements. Test objects are cavitation nuclei (small air bubbles and particles in water) whose size distribution is to be determined in a water tunnel. The ultimate resolution of the system including size determination by the digital picture processing system designed at the Drittes Physikalisches Institut is at present limited to 30 μm by the aberrations caused by the windows (thick PMMA) of the cavitation tunnel. The Nd:YAG laser proved to be a good alternative to a ruby laser. Bright phase holograms with high resolution could be made. The evaluation of the holograms shows as a result that the density of bubbles with a diameter greater than 30 μm was less than 0.1 per mm3 even in gassy water.

Date Published: 31 March 1989
PDF: 8 pages
Proc. SPIE 1026, Holography Techniques and Applications, (31 March 1989);

Published in SPIE Proceedings Vol. 1026:
Holography Techniques and Applications
Werner P. O. Jueptner, Editor(s)