Abstract: Thermally induced stress birefringence in laser resonators is eliminated by inserting a waveplate in the resonating cavity. The waveplate is chosen by matching its polarization transmission matrix to the polarization transmission matrices of the laser rod and a Porro prism used as an end reflector in the resonating cavity. This produces a total polarization transmission matrix in the resonating cavity which is independent of ray coordinates. Additional control of the polarization transmission matrix is provided using a Porro prism as a cavity reflector that has an antireflection coating on its roof to change the required phase advance angle of the waveplate.

Abstract: A multi cylinder, rotary valve, hot gas or fluid powered motor. An inner y having an output shaft, a plurality of cylindrical chambers, a corresponding plurality of sliding pistons, one within each chamber, and a pivot plate for supplying a reaction force to the pistons are mounted for rotation within a housing. A rod, attached within the housing, guides pressurized gas to the inner body through a rotary valve to supply the pressurized gas sequentially to the cylindrical chambers. Gas pressure on the piston and piston force against an angled pivot plate creates uncountered reaction forces tending to rotate the pivot plate and inner body. An output shaft attached to the inner body rotates to produce useful work.

Abstract: A solid state electronic circuit for controlling a reversible direct curr motor from a voltage source such that it may be rotated in either direction. The reversible direct current motor is connected into a bridge circuit with semiconductor switching elements which provide that the full supply voltage is available for starting in either direction. A pair of comparators receives input signals from a triangular wave generator and a signal source and in conjunction with a cross-fire protection circuit generates the drive pulses which control the semiconductor switching elements.

Abstract: A liquid mirror for high energy lasers. A working liquid such as mercury, used as the reflecting surface for laser light. Dielectric enhanced reflecting techniques can be used to increase significantly the amount of reflection from the working liquid. The liquid is contained in a pressure cell behind a transparent optical flat. By varying the pressure cell of the liquid, compensation for the aberration caused by heat absorption can be made. These same pressure changes can be used to correct for laser beam wavefront distortions produced elsewhere in the laser, director or atmosphere.

Abstract: A spectral scan by using a rotating spiralling toroidal mirror. The scan is made of a light beam from a source. A beamsplitter divides the beam into two components. One component is reflected off of a fixed mirror back to the beamsplitter. The second component is reflected off of the spiralling toroidal mirror back to the beamsplitter. As the mirror rotates, the pathlength constantly changes producing an interference pattern for all wavelengths within the range of the instrument.

Abstract: A single reflecting transmitter with improved performance capabilities. The mproved performance is achieved by using a modified surface called a wavy mirror. The wavy mirror has its focal distance a function of the angle measured around the axis of revolution. The wavy mirror is designed to reflect light into a predetermined pattern of controlled size and energy distribution. The reflection is oriented so that the light source does not obscure the reflected beam.

Abstract: A liquid propellant gun having a chamber adapted to receive a projectile liquid propellant and having a breech area containing a fuel injection system and a valve internally thereof and a bolt which is chambered within said valve and adapted to move from a projectile load to a fire position. The movement of the bolt from projectile load to fire position is done in one movement and this is possible in that the valve is able to hold high-pressure, making unnecessary a forward jogging of the bolt before firing.

Abstract: A machine with separate motion on two axes for toroidal polishing and gring of mirrors. The axes are at 90.degree. to each other and the amplitude of motion in each direction is independently adjustable. A portion of this machine can be modified to serve as an adapter unit that fits on standard polishing machines and can be removed leaving the standard machines able to function in the normal way. A gimbal assembly and stablizer bar are used to prevent twisting between a lens and a polishing surface.

Abstract: An infrared detector with narrow band tunable response. The detector is cosed of four layers of epitaxially grown material that is doped for selective wavelength absorption. The uppermost layer has a thickness much larger than the penetration depth of short wavelength radiation or the diffusion length of photo generated carriers near the surface. The upper layer is a heavily N-doped layer over a P-doped layer. The cut-on wavelength edge is determined by the amount of doping in the uppermost layer. By applying a reverse bias to this N-P junction, the cut-off absorption edge can be shifted to longer wavelengths.

Abstract: Two dimensional optical or electrical images are processed through a storage tube designed to yield the correlation function between the input images and stored images. By generating a series of stored images representing sine and cosine components of the Fourier transform, a fast, two-dimensional transform of the image is obtained.

Abstract: An oven with temperature-independent sections permits objects placed within t to experience the uneven heating and temperature gradient problems associated with real life conditions. The number of sections can vary depending on the gradients desired.

Abstract: A lateral photodetector having a segmented annular ring formed on the out surface. The segments are electrically interconnected to provide four interleaved output electrodes.

Abstract: Stripe-domain light deflectors are used within a lasing cavity. Magnetic trol of the deflectors permits tuning of the laser light to any wavelength in the range of light present.

Abstract: An optical notch filter having a suspension of small absorbing particles which blocks a narrow band of frequencies. The small absorbent particles are suspended as a colloidal system which can have either a solid, liquid or gas as host material. The absorbing particles can be incorporated in a solid matrix as a transmission filter or used on the surface of a mirror as a reflection filter. The filter can be tuned by an externally applied electric field or by applying hydrostatic pressure.

Abstract: A method and apparatus for improving combustion efficiency in external bung assisted projectiles by providing a stepped configuration of the projectile body and placing the injector ports in the recirculation zone created behind said step near the base of the projectile.

Abstract: A low altitude optical range finder for measuring the range from an aircr or other vehicle to the sea, ground terrain or other object. A source of narrow beam ultraviolet light is attached at one point on the vehicle and illuminates the object. An electromagnetically deflecting image intensifier and photodiode array combination is attached to another point of the vehicle (remote from the first point) for measuring the angle of arrival of the reflected ultraviolet light and, thereby, the range to the object.