Surface particulate laser power limiter which generates a plasma

摘要

The invention is a laser power limiter. The limiter incorporates a layer of plasma forming particulate material supported optically in front of a sensor. A focussing means is positioned optically forward of the particulate layer to concentrate incident threat radiation on the particulate layer. The position of the particulate layer relative to the focussing means is selected such that the focal area encompassed by concentrated incident radiation encompasses a sufficient number of particulates to insure protective plasma formation and to insure that damage level incident radiation will be concentrated to an energy level exceeding the plasma formation threshold of the particulate material. The particulate layer is supported on a rotating window such that new areas of the layer can be exposed to incident radiation after a damage radiation incident.