DPAL activities in Japan: update

Abstract

Activities on diode pumped alkali laser (DPAL) in Japan are updated. Since the last presentation in Chengdu, we have continued our DPAL research mainly targeting the development of tools for future scaling-up and high-efficiency operation. In particular, the focus is on a numerical simulation that combines computational fluid dynamics (CFD) and wave optics. To confirm the agreement between the experimental and simulation results, we designed and built several experimental apparatuses. Our latest gas-flow type DPAL produced 15.5 W output power with 80% slope efficiency based on the absorbed pump light. The agreement with theoretical prediction was excellent not only for output power but also for transverse mode shape and beam quality. Additionally, to accurately predict the performance of Cs DPAL, we measured the main reaction cross sections, namely, mixing and quenching reaction cross sections of the two P states of Cs with various hydrocarbon buffer gases. The main result of the repetitive pulsed operation by the cavity dumping technique and relevant numerical simulation is also discussed.