Laser‐Beam‐Induced Ultrasonic Waves in Glass‐II

A transient solution of the equations of motion of the medium have been obtained using electrostriction as a beam‐mixing mechanism. The effect of optical absorption in producing elastic waves is also considered. The magnitude of the pressure waves generated in some glasses are calculated. Experimental work with longitudinal waves in several glasses using a Q‐spoiled 1.6‐μ laser verifies the predicted linear dependence of pressure amplitude on laser‐spike energy. Measurements on the longitudinal wave produced in one glass verifies the predicted uniform generation of elastic waves in the volume of the sample. Either mechanism considered appears capable of producing catastrophic damage in glass in very intense laser beams.