Stimulated radiation emitted from streamer discharges in ZnO crystals at 300 K

Stimulated emission along streamer channels was observed for the first time in ZnO single crystals. Lasing was manifested by reduction of the width of the spectrum to 3–4 nm, formation of a mode structure, appearance of directionality, and an increase in the radiation intensity by four orders of magnitude. The maximum of the lasing spectrum was located in the range 389–406 nm and the energy of a single pulse ~1 nJ, the pulse duration was 0.3–1 nsec, and the power was 1–3 W. Stimulated radiation emitted from ZnO at 300 K was attributed to recombination in an electron–hole plasma in which the nonequilibrium carrier density was of the order of 10¹⁹ cm^–3.