Optical second harmonic generation of semiconductor lasers and laser arrays

The generation of blue and green laser light continues to attract attention in the field. As II–VI compound semiconductor lasers have achieved little success in generating high power blue and green light, this thesis focuses on another approach: generating blue and green laser light through second harmonic generation (SHG) of infrared semiconductor laser diodes and semiconductor laser arrays.; To achieve high SHG efficiency, we need to improve the mode quality of high-power semiconductor laser diodes. In the first part of this thesis, the study focuses on beam filamentation, which contributes to the poor mode quality of broad-area semiconductor laser diodes. Through theoretical and computer simulation models we developed, we studied the effects of external spherical and parabolic cavities on the beam filamentation and stability limit of the output laser beam with these external cavities. Experimentally, we verified our simulation results by measuring the near-field pattern of the output of a broad-area semiconductor laser. The dynamic behavior of the laser mode was also studied by using perturbation theory. The results of this study suggest that it is possible to obtain high power single mode operation through the use of external feedback.; With a single mode laser source, it becomes possible to employ resonant cavity structure to greatly enhance the efficiency of second harmonic generation. This is verified by our experimental results from SHG of a 1064nm single mode laser. In the experiment, high SHG efficiency and high SHG output power of 2.3W is achieved.