Modal characteristics and polarization dynamics of a continuous wave, diode-pumped, neodymium-doped in yttrium aluminum garnet laser

We have studied linear configuration diode-pumped Nd:YAG lasers as possible sources in coherent system applications. A theoretical development of the rate equations for continuous wave operation of Nd:YAG lasers is presented. A numerical simulation using the derived relations is then performed, and an analysis which identifies laser cavity design and pump beam geometries that enhance single frequency performance of these lasers is presented. An experimental investigation which confirms the expected effect of pump geometry on single frequency performance is also presented.; Stress induced birefringence in the laser crystal leads to an RF frequency split between orthogonal modes of the laser radiation. The sensitivity of the strain induced beat frequency to environmental changes in temperature or pressure presents the opportunity to use these lasers as intrinsic sensors. These lasers may also be used as sources in heterodyne applications. We discuss here the stability of the birefringent beat note and characterize the beat frequency of our lasers.; Finally, control of the laser polarization through coherent feedback is reported. Polarization switching is controlled by phase modulation of the coherent feedback signal and is accompanied by a damped sine modulation of the laser output. A discussion of modifications to the laser gain and the relaxation oscillation characteristics is also presented.