Submillimeter emission of CdS crystals pumped by intense light

Measurements of the power level of the pulsed submillimeter emission from CdS crystals under intense pumping at 77 and 300 K are reported. The peak power of the pump light reached 40 kW at 0.35 micron and 150 kW at 0.53 micron. Both bulk crystals and crystals grown by the Freriks method were studied. The threshold power density and emission wavelength of the samples for the cases of single-photon and two-photon pumping are shown. When the crystals are pumped with UV light, the pulsed submillimeter emission reaches a power level of 1.6 W at about 77 K. At pump power levels above 5 MW/sq cm, however, the submillimeter emission fades and eventually disappears. In the case of two-photon pumping, the pulse submillimeter power also reaches 1.6 W, but the emission does not fade at high pump levels. The decrease in the submillimeter emission power was accompanied by a simultaneous decrease in the intensity of the stimulated emission at the maximum of the emission line in the green part of the spectrum.