Abstract: The disclosure is directed to a distance measurement system for monitoring changes in distances between a source of illumination and a reflective surface. A white light source is directed into a transmit fiber optic element which terminates at a graded index lens (grin) which collimates the light. The light output from the grin lens passes through a single grating or a plurality of different gratings which dispose the white light into a spectrum which is directed to the reflective surface spaced therefrom at an unknown distance. The dispersed light bouncing off the reflective surface enters a receiver fiber optic device connected to a detection system for determining the spaced distance between the grating or gratings and the reflective surface.

Abstract: The invention provides structure and method for improving the efficiency of nonlinear optical processes where two light beams interact in a material to produce an output beam at a new frequency. Effective phase matching is accomplished by periodically removing the output beam energy so that it does not destructively interfere with the input. The invention can also be utilized to increase the efficiency of optical devices where partial phase matching is present without further adjusting the phase of the beams involved in the nonlinear interaction. The invention also provides effective beam phase matching where the beams passing through the nonlinear material cannot normally be phased matching by present methods.

Abstract: The purpose of the invention is to separate and detect a weak frequecy converted signal light beam (f.sub.s +f.sub.p) which is in the presence of a much stronger pump light beam (f.sub.p) at a slightly different frequency. Such a device is useful in laser radars and laser transmitted communication systems where the information is transmitted as a light beam of frequency f.sub.s but more conveniently selected at another frequency f.sub.s tf.sub.p. A specific example would be laser communication system using a carbon dioxide laser (10.6 micron wavelength 3.times.10.sup.13 Hz frequency). In some applications a cooled detector (required for most efficient detection at this frequency) may not be feasible and a frequency conversion detector, operating with uncooled detectors, would be preferred. The device comprises a nonlinear crystal which first receives a properly phased matched pump light beam (f.sub.p) and a signal light beam (f.sub.s) and produces a third beam (f.sub.s +f.sub.p) at a different frequency.

Abstract: The invention is directed to a measurement of rotation of a body with respect to a fixed inertial coordinate system by use of an oscillator that is rotationally symmetrical about one axis, a locking oscillator for injecting locking the rotationally symmetric oscillator to a selected frequency and state of polarization and measuring the polarized orientation of the oscillator with a polarization detector.

Abstract: A time shared transceiver laser system which may be rapidly switched between two subsystems while using the full power of the laser beam and which also generates a local oscillator beam required for coherent detection. A method of time sharing and for generating the local oscillator is disclosed.

Abstract: A non-scanning heterodyne optical imaging sensor which utilizes a multi-frequency coherent light source to provide a plurality of points of different frequencies on a single detector on which the image of an object is also projected. Each point acts as a local oscillator which is sensed/filtered to construct the image of the object without mechanical scanning.

Abstract: A method and apparatus are disclosed for testing nonlinear axicons utilizing holographic interferometry with simple, low cost, optical elements and with a new technique illuminating the entire surface under test.A similar method and apparatus are also disclosed as useful in testing plane or convex mirrors.