Lasing in zinc oxide single crystals exicted by an electron beam at liquid nitrogen and room temperatures

An improvement in the quality of zinc oxide crystals prepared by the hydrothermal method made it possible to increase the efficiency of laser resonators pumped transversely by an electron beam. At 300 K the efficiency was up to 10% for single-component resonators and 1% for multicomponent resonators. Nonequilibrium phonons were found to play an important role in the degradation of such a resonator.