High Energy Solid State Laser (SSL) for Ship Self-Defense

Ship defense requires 100 kW-1MW near diffraction-limited lasers with optimal wavelength and temporal format. Laser efficiency, beam quality, atmospheric transmission, thermal-blooming, and target interactions must be taken into account. Navy efforts to date have focused principally on the free electron laser (FEL) to fulfill this need due to the wide wavelength tuning range and projected high electrical-to-optical efficiency. FEL's will likely be implemented on next-generation electric ships, but for existing ships and for UAV's, the compact size of a solid-state laser makes it a very attractive option. 1 micron wavelength solid-state lasers are currently being pursued in many directed energy applications due to the maturity of this technology at high power. CW and high peak power solid-state lasers are each likely to be optimal for different targets and different thermomechanical interactions. With current solid-state laser technology, 1-5 kW average output power can be achieved in pulsed or CW mode at 1 micron, but typically with modest efficiency and >2x diffraction limited beam quality from a bulky system. CTI proposes a breakthrough laser architecture (validated in proof-of-concept demonstrations) to enable development of compact, power-scalable MOPA systems. The architecture implements a proprietary technology for achieving higher efficiencies than rod or slab architectures, with near diffraction-limited beam quality and minimal thermo-optic aberrations. Phase I conducted laser modeling and developed an engineering design for a kW-class MOPA based on this technology. Designs for > 100 kW power-scaled systems based on phased array of these MOPAs have been developed.