NONTHERMAL NATURE OF THE RADIATION GENERATED IN THE BULK OF ALKALI HALIDE CRYSTALS BY CO2 LASER PULSES.

A study was made of radiation flashes resulting from internal focusing of CO//2 laser pulses in samples of commercial-grade NaCl, KCl, and KBr crystals. The flashes were attributed to triboluminescence in cracks formed under the action of thermoelastic stresses near absorbing inhomogeneities heated by laser radiation to temperatures approximately less than 1000 degree K. This conclusion was confirmed by low values of the power density ( less than 10**7 W/cm**2) of the incident laser radiation at which the flashes were observed, by the results of investigations of the kinetics of these flashes and growth of the scattering, by the comparable rates of decay of the flash radiation in different parts of the spectrum, and by the difference between the spectra of the flashes from the spectrum of a Planck source.