Spontaneous and stimulated emission from electron-beam-excited gallium selenide

Stimulated emission from GaSe was obtained for the first time in a direction perpendicular to the C axis of a layered crystal. The wavelength of the emitted radiation was 609.1 nm, the threshold density of the electron beam was 20 A/cm², the electron energy was 120 keV, and the resonator length was 1.5 mm. The radiation was almost completely polarized and the electric vector was parallel to the C axis. A spectral analysis was made of the spontaneous and stimulated emission from GaSe under different conditions. The results obtained demonstrated the considerable advantages of the perpendicular geometry, compared with the conventional arrangement in which the resonator is formed by the cleavage surfaces.