High-power and high-efficiency operation of a CW-diode-side-pumped Nd:YAG rod laser

We have demonstrated high-power and high efficiency performance of a continuous-wave (CW) Nd:YAG laser with a simple and scalable side-pumping configuration. The maximum output power of 147 W was obtained in low brightness operation of M/sup 2/=45. The corresponding electric efficiency is 14.8%. To our knowledge, this is the highest value reported for diode side-pumped Nd:YAG lasers. By using a rate and photon transport calculation, we have estimated the pumping efficiency of 72%. High brightness operation was also carried out by applying bifocusing compensation of the Nd:YAG rod. The brightness of 272 MW/cm/sup 2/ sr with beam quality of M/sup 2/=5.9 and output power of 107 W was obtained at the electric efficiency of 11.6%. The brightness and the electric efficiency are comparable with those of industrial high-power CO/sub 2/ lasers that have been the first option for industrial applications.