Laser image intensifier

Claim 1

A low light level target laser image intensifier comprising: a conjugate resonator having a pair of spherical end reflectors, one of said end reflectors having modulatable reflectivity and being comprised of semiconductor material having the characteristics of changing its index of refraction in regions of minority carrier injection and increasing its reflectance in proportion to the density of electrons impinging upon it, said semiconductive material thickness is given by the relation d p lambda /2n wherein p is an integer, lambda is the predetermined wavelength of incident radiation from said lasing means normal to said semiconductive material and n is the index of refraction, having a thickness such that its reflectance varies from a maxima to minima for a given incident wavelength and is approximately equal to the electron penetration depth, said other end reflector being partially reflective to provide an output; active lasing means positioned with said conjugate reasonator between said end reflectors; and an electron image intensifier for modulating said modulatable reflector, said intensifier comprising: photoemissive means for emitting electrons from one surface in response to the impingement of an optical image on the opposite surface thereof; means for accelerating said emitted electrons; and means for focusing said accelerated electrons onto said modulatable reflector; whereby a low light level optical target image causing said impingement on said photoemissive surface is amplified by point to point lasing action between said end reflectors to produce an intensified image at said conjugate resonator output.