Optically excited bulk semiconductor lasers

Optical pump experiments on homogeneous samples provide a method of obtaining a clearer understanding of the details of laser action in semiconductors. For this reason, the quantum-mechanical rate equations for a bulk semiconductor laser that explicitly include a monochromatic light field as a pump source are developed. The theory treats general optical transitions and is valid for both pure and doped homogeneous semiconductors. The developed theory gives the intensity of the laser output in the entire region from below to above threshold as a function of the intensity and frequency of the pump field, the temperature, doping level, and material constants. Also the variation of the laser light frequency at threshold upon these parameters is given by the theory. Information about the dependence of the necessary pump intensity and frequency for threshold is gained. The theoretical calculations are compared with experimental measurements and found to be in general agreement.