Advanced Adaptive Optics (AO) for Laser Weapons in Heavy Turbulence

Adaptive optics are needed for high-energy laser (HEL) weapon systems when performance is limited by atmospheric turbulence. This typically requires adding an illuminator laser to produce a beacon by reflection from the target surface. Since a small spot is needed, the laser must be projected from the main aperture, complicating the optical design. With this type of beacon, performance is often degraded by speckle, spot size, and branch cuts. The mid-wave infrared (MWIR) thermal emissions from the spot heated by the HEL can also be used as the beacon. This beacon would not be affected by speckle and would have fewer or no branch cuts. We propose using finite element analysis, scaling law and wave-optics modeling, to do a detailed study of this concept.