New concept for laser fusion energy driver by using cryogenically-cooled Yb:YAG ceramic

Abstract

We propose cryogenic Yb:YAG ceramic as a novel reactor laser-driver material instead of conventional Nd:glass. Our research on cryogenic Yb:YAG revealed that both of stimulated emission cross section and thermal conductivity can be tuned well by controlling the material temperature. Using the obtained laser parameters in our experiments, a 1.3-MJ, 16-Hz diode-pumped laser system has been conceptually designed. The overall electrical-optical conversion efficiency is numerically calculated to be as high as 17%. The compact main amplifier with about 3000, m3 volume size would be realized by using the active mirror architecture. In addition, a 1-kJ laser system 'GENBU' has been designed as a milestone for the new driver.