Orthogonally Polarized and Double-Resonant Nd:YAG Lasers Pumped by Birefringent Dual Points

Abstract

We investigated a dual-point pumped Nd:YAG laser that emits two beams, where the dual-point pumping occurs through the birefringent walk-off effect of pump light in a uniaxial crystal. By using dual-point pumping, two-beam and parallel oscillations were obtained, where the two beams were orthogonally polarized, and the polarization direction of each beam was identical to that of the corresponding pumping point. The polarization extinction ratio of an ordinary light pumped beam was 31.75 dB, and the polarization purity of extraordinary light pumped beam was 31.25 dB. Compared to that of conventional single-point pumps, the slope efficiency of the output power increased from 16% to 22%, and the maximal output power increased from 1.05 to over 1.66 W. The effects of polarization of dual-point pump light on the power, efficiency, and polarization of the two-beam output were experimentally analyzed. The performance of this dual-point pumped laser was also compared with that of a single-point pumped laser, and the results revealed its capability of increasing the output power.