Compact and Efficient Cooling Techniques for High Energy Solid State Lasers

State-of-the-art diode-pumped solid-state laser (SSL) technologies make it possible to design 100 kWo electric laser weapons that are compact enough to be packaged into tactical platforms. These electric laser systems pose unique challenges in that the cooling system must dissipate heat loads that are often ten times greater than the laser optical output with high heat fluxes over large surface areas with limited heat rejection. Single-phase cooling schemes require high coolant flow rates to ensure constant laser operating temperatures and large water chillers or refrigeration cycles, resulting in large and bulky cooling systems that are not practical for tactical platforms. In this effort RTI will determine the feasibility of using a combination of two-phase evaporative spray cooling (ESC), thermal energy storage (TES) and refrigeration techniques to meet the volume, mass and power consumption metrics for high-power SSLs required by DARPA. Feasibility will be established through cooling experiments and system level calculations. The reduction in cooling system weight enable by RTI¡¦s technology for both long run time illuminator laser (,d 300 sec), and short run time 100 kWo weapons (30sec) will provide a cooling system small enough for deployment on tactical platforms