High-symmetry gradient-doped 0.17-0.38-0.17 at% Nd:YAG laser crystal for dual-end pumping configurations.

Abstract

High-symmetry gradient-doped laser crystals were specifically engineered for dual-end-pumped configurations to enhance laser performance. Two gradient-doped laser crystals were successfully fabricated, a 0.17-0.38-0.17 at% Nd:YAG rod and a 0.18-0.32-0.18 at% Nd:GdYAG rod. The output power, beam quality, and thermal characteristics were systematically compared with a conventional 0.6 at% uniformly doped Nd:YAG crystal. At 20 W pump power, the axial temperature differential in the gradient-doped crystal measured 37°C, representing a two-thirds reduction compared to the uniformly doped 0.6 at% Nd:YAG reference. The 0.17-0.38-0.17 at% Nd:YAG rod achieved a maximum output power of 14.47 W with 51.7% slope efficiency, representing 45.1% and 62.1% improvements respectively over uniformly doped 0.6 at% Nd:YAG. At 9 W output power, the beam quality factors were measured to be M_x² = 2.347 and M_y² = 2.217 for the 0.17-0.38-0.17 at% Nd:YAG crystal. This work establishes gradient doping as an effective strategy for simultaneous improvement of thermal management, power scaling, and beam quality in diode-pumped solid-state lasers.