Development of high energy and high average power diode pumped laser drivers for inertial fusion energy systems

This paper presents a decadal review of conceptual and working laser systems developed at Lawrence Livermore National Laboratory for Inertial Fusion Energy (IFE) power plants. The Mercury Laser Project, which was a groundbreaking diode pumped solid state laser driver designed for IFE, required the development of average power capabilities of all the core elements of the laser. At the completion of the project the system achieved its core requirements: operating at 10 Hz, ⪆ 50 J, for ⪆300000 shots proving out steady state operation of a high-fidelity pulsed laser system. As the National Ignition Facility (NIF) approached completion, a new project called Laser Inertial Fusion Energy (LIFE) was initiated which took the lessons learned from NIF, Mercury, and latest technology to propose power plant scale laser systems in an integrated design with targets, injection, chamber, and balance of plant. These designs used only modest extensions of existing laser technology to ensure near term feasibility. The predicted performance of the laser design met or exceeded plant requirements: 2.2 MJ pulse energy produced by 384 beamlines at 16 Hz, with 18% wall-plug efficiency. High reliability and maintainability are achieved in this design by mounting components in compact line-replaceable units that can be removed and replaced rapidly while other beamlines continue to operate. Following this design phase an opportunity arose through High-Repetition-Rate Advanced Petawatt Laser System (HAPLS) project where the pump laser for this system is a scaled down version of the LIFE laser.