Researchers at Lawrence Livermore National Laboratory (LLNL, Livermore, CA) recently demonstrated a diode-pumped Nd:YAG laser with a CW output power of 155 W at 1064 nm. The device was pumped by a 25-bar stack assembly of microchannel-cooled 1.5-cm-long AlGaAs laser diodes; output from each diode bar was optically conditioned with cylindrical microlenses to reduce the divergence angle. The resulting 550-W output was then focused with a fused-silica lens duct onto the Nd:YAG laser rod. The output coupler was mounted away from the rod. The optical-to-optical slope efficiency of the system was 33%.
According to LLNL researcher Camille Bibeau, because the high pump laser intensity could damage the rod, protective undoped YAG end-caps were diffusion bonded to each rod end. The overall dimensions of the laser system are 5 x 30 cm and, says Bibeau, it is this compactness, combined with the relative simplicity and low cost of the technology, that is likely to lead to applications for the laser design in medicine, radar, manufacturing, and material processing.