LD-Pumped Kilo-Joule-Class Solid-State Laser Technology

In this chapter, we report our latest work on the technical development of the cryogenically cooled Yb:YAG-ceramics laser as scalable technology toward achievement of repetitive kilo-joule-class lasers. In our first trial, we obtain a high small signal gain of 20.4 with a high stored energy of 149.0 J using a conductively side-cooled Yb:YAG ceramic multi-disk laser amplifier operating at 100-K cooling temperature. In the second trial, we obtain 117-J nanosecond pulsed laser output with a cryogenic-helium-gas face-cooled Yb:YAG ceramic multi-disk laser amplifier. In this study, we obtain 42.3% energy-extraction efficiency from the energy stored in the Yb:YAG ceramic disks. We also determined the specifications of the face-cooled laser amplifier designed for repetitive operation by flowing helium gas on the end faces of the Yb:YAG ceramic disks. The feasibility of a practical design for kilo-joule-class diode pumped solid state lasers with a cryogenically cooled Yb:YAG ceramic disks was demonstrated by the developed high-gain and high-efficiency laser technologies.