Use of quasicontinuous laser pulses in polarization-optical investigations of the damage of matter caused by laser radiation

A description is given of the apparatus used in a photoelastic investigation of the dynamic effects of the loading and damage caused by high-power laser pulses. The use of a quasicontinuously emitting ruby laser as a source of monochromatic background radiation makes it possible to achieve a time resolution of 8X10^–8 sec in continuous recording of the stress pattern in the irradiation zone. A description is also given of the construction of composite photoelastic sensors which can be used to study some dynamic effects which appear under the action of laser radiation on opaque substances. The appearance of acoustic vibrations under the action of laser pulses on matter is reported. The measured values of the velocities of longitudinal and transverse sound are used to calculate the Poisson ratio and Young modulus of a composite ÉD6–MA epoxy material.