In-Cavity Laser Modulation Study

摘要

Theoretical and experimental study was performed to investigate a laser modulation technique capable of providing a flat frequency response over the range of 30 cps to 30 mc/s with a modulation index of 0.5 or greater. The technique involved the introduction of controllable losses to the laser cavity by alternate alignment and misalignment of the cavity reflectors. This was to be accomplished by insertion of an electro-optic prism in the cavity and varying the angle of deviation of the exit beam from the prism by electrically controlling the magnitude of the index of refraction of the prism. The transmission losses associated with the electrooptic prism were experimentally found to be greater than the gain of the laser cavity. Thus, oscillations could not be maintained with the electro-optic prism in the cavity. The major factors contributing to the transmission losses were found to be reflection losses and an inherent birefringence of the crystalline materials. Pertinent theoretical discussions and experimental results are included in the report. (Author)