Design and Performance of a Diode-Pumped Nd:Silica-Phosphate Glass Zig-Zag Slab Laser Amplifier for Inertial Fusion Energy

A high-energy, high beam quality, diode-pumped 1053-nm Nd:silica-phosphate glass laser amplifier has been designed, constructed and tested in order to verify the conceptual design of HALNA (high average-power laser for nuclear-fusion application): a diode-pumped solid-state laser based on a water-cooled zig-zag slab optical geometry. This amplifier yields an 8.5 J output energy per pulse at 0.5 Hz in a 20 ns pulse of two times the diffraction limit beam quality with an optical-to-optical conversion efficiency of 10.9%. This is the first demonstration of a diode-pumped solid-state laser amplifier for the inertial fusion energy (IFE) driver. The detailed considerations on the optical and thermal designs of the novel amplifier architecture are discussed. The experimental results revealed that the primary requirements for the IFE driver, such as diode-pumping, energy storage and extraction efficiencies, and beam quality have been fulfilled.