Development of LD pumped 10 J×10 Hz Nd:glass slab laser

Abstract

The concept of a diode-pumped solid-state laser (DPSSL) driver for inertial fusion energy (IFE) has been introduced by Krupkel (1989), and Naito et al. (1992). Orth et al. (1996) has designed in detail a DPSSL driver using He gas cooling. In the study, we have developed a conceptual design of a 803-nm laser-diode (LD) pumped water-cooled Nd:glass slab laser driver for IFE. The IFE power plant KOYO has the basic design specifications of 4 MJ output at 351 nm and 12 Hz repetition rate. For the laser gain medium, we have adopted the glass host which can be produced in large sizes with good optical quality. The HAP-4 glass (HOYA) has the appropriate material parameters for designing a high power and repetitively operating laser system. The slab dimensions were determined under the several operational constraints. Zig-zag path slab has an advantage that the laser beam does not pass through the cooling medium as it propagates by means of total internal reflections. Using this advantage, the slab is cooled on both sides with flowing water having high cooling capability. As a first step of a driver module development for the IFE, we are developing a small scale DPSSL module which has 10 J x 10 Hz laser output at 1053 nm. The module is the smallest size to confirm the conceptual design of the driver module.