An optical tracker includes a plurality of detectors (20, 22), each of which is associated with an etendue-preserving concentrator (27, 28) that directs radiation to it. The concentrators (27, 28) associated with complementary detectors (20, 22) are oriented at angles with respect to each other such that their complementary angle-sensitive regions overlap. As a consequence, the outputs of the detectors can be used to aim the tracker even though the concentrators direct radiation to the detectors...

An improved knife edge system which enables testing of even high numerical aperture optics is achieved by using a microscope objective to gather the light from a small pinhole and fill a large optic under test, and in conjunction with a special eye piece permits viewing of the surface of the optic under test.

An optically pumped solid-state laser system includes a rod (50) of laser material and a plurality of flashlamps (66) for pumping the laser. A surface for reflecting radiation from the flashlamp (66) to the rod (50) follows a set of curves (96). Each curve (96) is the locus of points whose distances outside the rod (50) and the lamp (66) to a pair of starting points on the other side of a base line (74) are a constant value such that the locus includes a lamp cusp (70).

A dual-section spatial modulator transmitter consists of a collector surrounding a source of radiation to collect the energy from the source and form it into multiple beams. The collector is configured in two sections, a rotatable section and a stationary section such that spatial modulation is obtained by rotating only the rotatable section.

A beam projector is provided by a plurality of coded reticles mounted on a spinning disc and illuminated by a laser source. In order to maintain a constant irradiance on a receiver variably located in space a pseudo-zoom assembly is provided including a moveable source and/or condenser optics. Also, plural focal length optics are employed to expand the range over which the constant irradiance is maintained beyond that realizable by the pseudo-zoom assembly itself.

Covert stop action photography is achieved by using an illuminator comprising a solid state laser which operates in the 0.8 to 0.9 micron region and which is optically pumped by incoherent energy in combination with infrared film which is sensitive in the same spectral region.

This optical velocimeter may be installed in an aircraft to measure the true airspeed and the angles of attack and of sideslip of the aircraft. Alternatively, the velocimeter may be mounted in a wind tunnel to measure the velocity of the airstream passing through the wind tunnel. In either case, the points of reference for measurement are the large number of aerosol particles that are entrained in the air and are assumed to have the same velocity as the oxygen and nitrogen molecules of the air i...

Improved laser system gain is achieved by using Gadolinium to totally replace the Yttrium in a Lithium Yttrium Fluoride (YLF) host crystal so as to increase the amount of Neodymium which can be doped into the host crystal.

A wide field of view-narrow band detection system including a radiation responsive member and optical filter is provided by employing optimal angle cones to simultaneously control field of view, throughput and angles impinging on the optical filter.

An optical system to permit two detectors to see the same field of view includes an angle converting cone, for mixing radiation from a field of view so that it can be applied to two detectors, and a lens for focusing the radiation onto the cone.