Distributed feedback laser in CdS

Distributed feedback laser was observed in CdS with a simple DFB structure under electron beam excitation. The lasing characteristics such as the temperature dependence and the time dependence of the laser were examined. The line width of the laser spectrum was found to be less than 0.8 Å. Compared to a conventional laser, the lasing wavelength was insensitive to temperature. The dependence of the lasing wavelength on temperature is explained by the change of the refractive index. In some samples the DFB lasing was observed to occur only at the start of the excitation pulse and the pulse width was much shorter than that of a conventional laser. This phenomenon is explained by a gain switching mechanism.