US Patent 10320141 Hard target detection for optical systems

A system and method for detecting hard targets in a free-space laser system includes a laser, an optical detector, and electronics. The laser is configured to emit a laser beam along an optical path through transmitter optics into a field of view. The optical detector is positioned along a laser transmitter path and configured to receive retroreflections of the laser beam. The electronics are configured to determine if an output of the optical detector is indicative of presence of a hard target within the field of view, and control the laser to a safe state if the output is indicative of presence of the hard target.