High Heat Flux Laser Diode and/or Solid State Laser Cooling for Airborne and/or Spaceborne Directed Energy Applications

Diode laser present one of the most challenging thermal problems in industry. The small footprint and very high power levels combine to create extremely high heat fluxes in the vicinity of the diode. Tese heat flux levels raise the diode temperature,leading to lower lasing efficiency, wavelength shifts, and reduced diode lifetime. The cooling problem becomes even more difficult when combined with requirements for low pressure drops, low coolant flow rates, reliability, long operating life, ease ofattachment, small volume, and low cost.The best performing thermal management solutions available in the marketplace today are provided through micro-impingement and microchannel cooling methods, which offer thermal resistances as low as 0.035 K-cm2/W. Many customers, however, have expressedinterest in achieving these thermal resistance levels at much lower coolant flow rates. To accomplish this, the Phase II effort will examine novel 2-phase microchannel designs, diamond cooling, and heat transfer enhancement approaches within themicrochannels.