Development of High-Power Quasi-CW Laser Bar Stacks With Enhanced Assembly Structure

We report on our recent development of quasi-continuous-wave 940-nm laser diode (LD) bars with passive cooled type. The 10 LD bar stacks with a narrow pitch of 1.54 mm have demonstrated a high output power of 10.1 kW, corresponding to 1 kW/bar, under 200- $\mu \text{s}$ pulses at 50-Hz operating frequency. The maximum conversion efficiency of 58% has been achieved at an output power of 300 W. In condition of 1000 $\mu \text{s}$ pulses at 10-Hz operating frequency, we have achieved an output power of 0.93 kW and a conversion efficiency of 59%, respectively. We consider that the LD bar stacks are suitable for diode pumped high-energy class solid-state lasers.