Analysis on Thermal Management of High Power Diode-Pumped Lasers

Because the emitting wavelength of the laser diode (LD) pump source is matched with the absorption spectrum of the laser medium, high power diode-pumped lasers greatly reduce the useless heat into the laser medium, and alleviate the impact of thermal effect. However, with development of the output power of lasers toward a MW power level, thermal effect of the laser medium seriously impacts the improvement of output power and beam quality, which has become a bottleneck of the further upgrade of high power lasers. From different perspectives of thermal management technologies, this paper compares the thermal management methods of high power output diode-pumped slab lasers, heat capacity lasers, the US Mercury system, fiber lasers, and diode-pumped alkali vapor lasers (DPALs). Furthermore, it analyzes the principle of DPALs to realize high efficient thermal management, indicates that DPALs are highly promising for power scaling into the multi- kilowatt regime, and expounds the potential application of DPALs as high power lasers in the fields of directed energy and inertial fusion energy (IFE).