Intermode scattering effects in laser emission spectra of platelet and acicular CdS-type single crystals subjected to one-photon excitation

An investigation was made of the laser emission spectra of platelet CdS, Zn_x, Cd_1–xS, and CdS_1–xSe_x, single crystals and acicular CdS single crystals at T = 4.2, 77, and 300 °K. Lasing developed in partial resonators (rectangular insulating microboxes or microprisms) and the emission consisted of total-internal-reflection modes characterized by the highest Q factor. Radiation emerged in vacuum as a result of intermode scattering of photons (without a change in the frequency) out of the total-internal-reflection modes into modes with lower Q factors, which could be emitted.