Abstract: An electrode assembly for a gas or metal vapor discharge device is disclosed. A pair of electrode assemblies each comprising thoriated tungsten with an alloy composition of tungsten (W) and from about 2% to about 3% of thorium dioxide ThO2 are located at opposite ends of the discharge chamber of the discharge device. The tip of the electrode preferably has four slots equally spaced around its circumference and a groove at its outermost edge. The tip of the electrode provides mechanical flexibility that inhibits the cracking of the thoriated tungsten electrode when it is mounted in the discharge device. Each electrode assembly further comprises a copper spacer, preferably I-shaped in cross-section, brazed against the base of the electrode and against a vacuum flange. The pair of electrode assemblies confines the discharge of the discharge device between the tips of the electrodes and inhibits the arc condition from finding its way to delicate vacuum seals.

Abstract: An interferometrically tuned laser resonator for selectively resonating at desired wavelength or fluorescent line. A dielectric reflector having reflectance characteristics which shift toward shorter wavelengths at incident angles not normal thereto is rotatably mounted at one end of a laser cavity along its axis. Rotation of the reflector permits adjustment of the incidence angle to obtain maximum cavity gain at a desired fluorescent line over adjacent competing lines.

Abstract: A laser device for generating frequency-doubled laser pulses at maximum eciency. A laser rod is optically pumped to radiate unpolarized light at 1.064.mu. wavelength for transmission within a ring-type resonator defined by a flat mirror and a turning prism. The light from one end of the rod is linearly polarized by a beam splitter into two parallel beams of orthogonal components which are transmitted through an 0.532.mu. output mirror, a frequency doubler phase matched for one component, and a Q-switch, to the turning prism for return along the beam of the other component to the beamsplitter. The output mirror, doubler and Q-switch are substantially ineffective during the pumping cycle, and because the component beam axes are reversed, the light does not return to the rod for stimulating light emission. After peak level pumping, however, the Q-switch is biased to rotate each component one quarter wavelength and return the components to combine and reenter the rod for stimulated light emission.

Abstract: A laser device for generating a high power output in a pulse transmission de. The laser corrects for thermally induced birefringence losses. A flashlamp is actuated to cause an atomic population inversion in an adjacent laser rod. Thereafter, population inversion in the rod is decreased and the laser intra-cavity optical field increased by a linear resonator. This resonator includes a mirror, the laser rod in a cavity generating a single laser beam, a birefringent crystal converting the single beam into a pair of beams each having a different polarity and vice versa on return, a half-wave plate placing the polarization of one of the beams in correspondence with that of the other beam, and a reflecting polarizer reflecting only that polarization through a Q-switch such as a Pockel's cell, inactivated, and to a second mirror. The second mirror reflects the pair of beams back through the switch and to the polarizer, from which they return to the birefringent crystal and laser rod.

Abstract: A laser device for generating high input power by minimization of surface flection losses between adjacent elements of the device. A laser medium having an index of refraction substantially greater than 1.5 is fluid cooled in a sealed tube by an optically clear cooling medium having a substantially lower refractive index. The indices of the laser and cooling mediums are matched to each other by thin film coatings of index matching material attached to the laser medium, each coating having a thickness of one quarter of the lasing wavelength.

Abstract: A narrow angle, narrow bandwidth optical receiver system for detecting light rays reflected from a predetermined area illuminated by a laser beam having a known wavelength. A large collecting lens having a small field of view receives incoming reflected rays which are collimated by a pair of relay lenses having a narrow bandwidth, triple cavity, single element interference filter positoned therebetween. The filtered rays are processed by a photomultiplier tube and a CRT display to illustrate signals of interest within the illuminated area. An alternate embodiment provides a cone element to receive filtered rays from relay lenses for decreasing the size of the receiver system.

Abstract: A laser system for ocean radar applications having a resonant chamber for producing a pair of homogenized, singularly polarized output beams having identical pulse widths and energies. A quarter wave plate is inserted within the optical path of the resonant chamber and rotates the birefringence effects of a laser crystal positioned within the chamber to generate a pair of homogenized, orthogonally polarized beams. A selected one of the orthogonally polarized beams is transmitted through a half wave plate and joins with the remaining beam for passage through a telescope assembly to minimize the cross-sectional area of the beams. A doubler crystal receives the telescoped beams and doubles the frequency thereof to form the pair of homogenized output beams having light energy in the green spectrum.