Improvement of thermal effect of laser crystal using multi-channel and indium-soldered technique

To solve the thermal dissipation problem in laser diode (LD) end pumped solid state lasers, a novel heatsink was developed based on multi-channel and indium-soldered technique. Under 28 W pump power, 8.7 W (in traditional indium-wrapped heat-sink), 10.5 W (in indium-wrapped multi-channel heat-sink) and 11.9 W (in indium-soldered multi-channel heat-sink) output were obtained with the Nd:GdVO₄ laser crystal, respectively. Corresponding optical-optical efficiencies are 31%, 38% and 44%, and the slope efficiencies are 36%, 42% and 49%, respectively. In addition, 17.5 W output was achieved under 40 W incident pump power when the indium-soldered multi-channel heatsink was used, and no saturation was observed. From the aspects of maximum output power, optical-optical efficiency and slope efficiency, the indium-soldered multi-channel heat-sink showed best performance among three kinds of heatsinks. And the advantage was further certified by measuring the length of thermal lens and fundamental mode output power.