Liquid-Nitrogen-Cooled Ti: Al2O3 Laser

摘要

At 93 K, sapphire (Al2O3) has much better thermal properties than at roomtemperature. By taking advantage of the improved thermal properties, a Ti:Al2O3 laser is operated with 350 W of output power under thermal steady-state conditions. Model calculations of thermal lensing and higher order thermo-optic aberrations indicate that the output power capability is 200 times larger at 77 K than at 300 K, consistent with our results. The interest in development of high-power solid-state lasers for applications such as materials processing and remote detection makes the study of thermo optical distortions of great practical importance. Since the refractive index is a function of temperature, a temperature gradient causes optical distortions, which affect the optical properties of the laser cavity. In addition, differential expansion caused by the temperature gradient produces stress-induced optical distortions.