Abstract: A method is presented utilizing a holographic approach for linear phase conjugation to compensate for atmosphere-induce aberrations that severely limit laser performance. In an effort to improve beam quality, fine aim point control, and laser energy delivered to the target, aberration compensation is accomplished using holographic adaptive tracking that utilizes a spatial light modulator as a dynamic wavefront-reversing element to undo aberrations induced by the atmosphere, platform motion, or both. This aberration compensation technique results in a high fidelity, near-diffraction limited laser beam delivered to the target.

Abstract: A method for detecting, tracking and locating submarines (24) utilizes pulsed coherent radiation from a laser (12) that is projected down through a water column, with particles in the water producing speckle from backscatter of the random particle distribution, with correlation of two closely time-spaced particle-based speckle patterns providing an intensity measurement indicative of the presence of a submarine. Subsurface submarine movement provides a subsurface wake which causes movement of particles such that two closely-spaced “snapshots” of the returns from particles in the same water column can detect particle movement due to the wake. The magnitude of the speckle pattern change indicates particle movement. In one embodiment, the return signals are imaged onto an intensified CCD or APA array that capture two successive laser pulses through the utilization of dual pixel registered cameras.