Efficient 1.8-kW diode-pumped CW Nd:YAG rod laser

Summary form only given. As laser diodes (LDs) have recently been rapidly increasing their output power, high power all solid-state lasers based on LD pumping are currently subject to active R&D. One target of a LD pumped solid-state laser is an easy maintenance, compact, high power laser system. A laser system with multi-kW output power could be a useful tool for welding, cutting and drilling. In order to develop compact high-power solid-state lasers, pump power density is the key parameter. In our previous paper, we reported the development of a 1-kW CW Nd:YAG rod laser with pump power density up to 380 W/cm, which is, to our knowledge, the highest pump power density for a rod type Nd:YAG laser. In this paper, we report the experimental results of 1.8-kW operation with pump power density up to 380 W/cm, and experimentally investigate the energy transfer from electrical input to laser output.