Abstract: A polarizing beam splitter for splitting a non-collimated light beam of a given wave length into two sub-beams, each of a different state of polarization, has a substrate provided with a polarizing stack of thin layers and a compensating means for compensating retardation of the light beam occurred in passing through the polarizing stack.

Abstract: An anti-theft bolt guard is shown having a cylindrical body (65) for placing over a nut (60) of an installed bolt (30). Third washer (45) engages bolt (30) and the body (65) is affixed to the bolt (30) with a threaded circular guard nut (85). The guard nut (85) is tightened with a special key (120). A fourth washer (46) engages the guard nut (85) and an adhesive (57) material may be inserted. The guard nut (85) is then sealed off with the insertion of a press fit seal cover (95) thus providing a device that prevents easy access to the nut (60) and removal of the bolt (30).Protection for the exposed head (32) of a bolt can be obtained by inserting the bolt (30) through a head guard (35) where a press fit head cover (25) is inserted in the first end (36). An adhesive (57) can be inserted to increase the difficulty of removal of the protection device.

Abstract: A gas discharge laser includes one or more birefringent layers in a multi-layer reflector that provides such a large difference in reflection of light polarized linearly in two mutually perpendicular directions that the laser generates 100% linearly polarized light in one direction only. In the other directions the reflection is insufficient to obtain stimulated emission.

Abstract: A gas discharge laser comprises a multilayer coupling-out mirror including a plurality of alternate dielectric layers of high (H) and low (L) indices of refraction. A radiation-attenuating film element, preferably a metal film, is sandwiched between a pair of L dielectric layers located near the mirror substrate to provide an asymmetrical characteristic whereby the laser becomes relatively insensitive to light reflected towards it, which in turn reduces any tendency toward fluctuation in the intensity of the laser beam. The device is especially useful in systems for reading out information from a video record carrier wherein the reflected light is modulated and if returned to the laser would produce output power fluctuations therein.

Abstract: A multilayer reflector of which the last layer most remote from the substrate and having a high refractive index is vapor-deposited from a mixture containing a metal or oxide of an element from group 4b of the periodic table and a metal oxide from the group of beryllium oxide, magnesium oxide and calcium oxide, is particularly resistant to hydrogen and ultraviolet light and is hence suitable for application in a laser which is to have a long life.

Abstract: A mother for manufacturing long-playing video records is provided by (1) selectively exposing a photoresist disposed as the outer layer on a substrate comprising a disc-shaped plate, a thin layer of base material, e.g., an oxide of nitride, adhering to the plate and a thin metal layer, e.g., chromium, silver, nickel or titanium, coating the base material layer, (2) removing non-activated sections of the photoresist layer and (3) sputter or chemically etching the thin metal and base material layers in sections corresponding to the removed sections of the photoresist layer.

Abstract: A gas discharge laser in which a plane parallel transparent plate whose normal encloses an angle with the axis of the laser tube equal to the Brewster angle is arranged in at least one of the ends of the laser tube. The plate is secured to the adjacent reflector so that the plate can easily be replaced.