Stimulated emission and lasing in Cu(In,Ga)Se sub(2) thin films

Stimulated emission and lasing in Cu(In,Ga)Se sub(2) thin films have been demonstrated at a temperature of 20 K using excitation by a nanosecond pulsed N sub(2) laser with power densities in the range from 2 to 100 kW cm super(-2). Sharp narrowing of the photoluminescence band, superlinear dependence of its intensity on excitation laser power, as well as stabilization of the spectral position and of the full-width at half-maximum of the band were observed in the films at increasing excitation intensity. The stimulated emission threshold was determined to be 20 kW cm super(-2). A gain value of 94 cm super(-1) has been estimated using the variable stripe length method. Several sharp laser modes near 1.13 eV were observed above the laser threshold of I sub(thr) ~ 50 kW cm super(-2).