Abstract: A method for optically pumping a gain-medium with partially polarized or unpolarized pump-light having a wavelength at which that gain-medium has an absorption that is dependent on the polarization plane of the pump-light is disclosed. The pump-light is directed into the gain-medium. The strongest-absorbed polarization component of the pump-light is substantially absorbed and the weakest-absorbed polarization component is partially transmitted by the gain-medium. The polarization plane of the transmitted component is rotated through 90 degrees and the polarization-rotated pump-light is directed back into the gain-medium, wherein it is substantially absorbed.

Abstract: A method for optically pumping a gain-medium with partially polarized or unpolarized pump-light having a wavelength at which that gain-medium has an absorption that is dependent on the polarization plane of the pump-light is disclosed. The pump-light is directed into the gain-medium. The strongest-absorbed polarization component of the pump-light is substantially absorbed and the weakest-absorbed polarization component is partially transmitted by the gain-medium. The polarization plane of the transmitted component is rotated through 90 degrees and the polarization-rotated pump-light is directed back into the gain-medium, wherein it is substantially absorbed.

Abstract: A liquid crystal light valve is provided which comprises a pair of glass cover plates. Transparent electrodes are located on the interfaces of each cover plate. The electrodes are electrically connected to alternating current sources. Insulating films are placed on either side of a liquid crystal material to provide electrical and chemical isolation between the liquid crystal and the electrodes. Spacers are employed to maintain a suitable gap between the insulating films and to prevent the liquid crystal from escaping. Positioned on the side of the liquid crystal from which writing light enters the light valve are, respectively, a dielectric mirror, a light blocking layer and a photoactive layer. According to the present invention, the photoactive layer comprises hydrogenated amorphous silicon which is configured as a photodiode with a junction layer facing the writing light.

Abstract: An optical system and method for image sampling in a video projection system is provided. A beam of illumination light is passed through a first beam-splitting polarizer to provide a first beam of a first polarization state and a second beam of a second polarization state. The first beam is passed through a second beam-splitting polarizer which is oriented at 90.degree. with respect to the first prism. The light from the second prism is then provided to a modulation device which produces a polarization modulated image in reflected outgoing light. The reflected outgoing light is passed through the second prism such that a first portion is directed to an image display screen and a second portion, which contains an image sample, is directed toward the first prism. The image sample is reflected by the first prism and provided to an image detector which detects characteristics of the sample. The detected characeristics are utilized to control the outgoing light.

Abstract: A plasma tube for a gas laser includes a series of heat webs and insulative spacers between the heat webs, with tungsten bore insert members supported by the heat webs and having aligned apertures defining a laser discharge path. To produce the plasma tube, the heat webs, spacers and other connected components are assembled in a vertical stack outside the ceramic tube of the laser, with a stacking gauge which helps assure that the heat webs are correctly spaced apart within close tolerances. The heat webs lie adjacent to annular metallized areas on the inside surface of the ceramic tube when the assembly is inserted into the tube, which is precision-formed ceramic tubing. The tube assembly is heated in vertical orientation to expand the heat webs diametrically so that they engage outwardly against and are brazed to the metallized areas of the ceramic tube.

Abstract: A plasma tube for a gas laser includes a series of heat webs and insulative spacers between the heat webs, with tungsten bore insert members supported by the heat webs and having aligned apertures defining a laser discharge path. To produce the plasma tube, the heat webs, spacers and other connected components are assembled in a vertical stack outside the ceramic tube of the laser, with a stacking gauge which helps assure that the heat webs are correctly spaced apart within close tolerances. The heat webs lie adjacent to annular metallized areas on the inside surface of the ceramic tube when the assembly is inserted into the tube, which is precision-formed ceramic tubing. The tube assembly is heated in vertical orientation to expand the heat webs diametrically so that they engage outwardly against and are brazed to the metallized areas of the ceramic tube.

Abstract: A plasma tube for a gas laser includes a series of heat webs and insulative spacers between the heat webs, with tungsten bore insert members supported by the heat webs and having aligned apertures defining a laser discharge path. To produce the plasma tube, the heat webs, spacers and other connected components are assembled in a vertical stack outside the ceramic tube of the laser, with a stacking gauge which helps assure that the heat webs are correctly spaced apart within close tolerances. The heat webs lie adjacent to annular metallized areas on the inside surface of the ceramic tube when the assembly is inserted into the tube, which is precision-formed ceramic tubing. The tube assembly is heated in vertical orientation to expand the heat webs diametrically so that they engage outwardly against and are brazed to the metallized areas of the ceramic tube.

Abstract: A dye laser is stabilized for operation at a narrow line width by a control system which utilizes two reference interferometers.One reference interferometer has a small free spectral range for stabilizing the frequency of operation of the dye laser at the relatively narrow line width, and the other reference interferometer has a free spectral range substantially larger than the first reference interferometer.The dye laser is servo locked to a side of a transmission fringe of the first reference interferometer to maintain operation at a selected frequency with the narrow line width in the absence perturbations that can cause a mode hop.When a perturbation does cause a mode hop, the second reference interferometer detects the extent and the direction of the mode hop. It then automatically stops the scanning system of the dye laser, resets the servo back to the selected frequency and restarts the scanning system of the dye laser in operation at the selected frequency, all within a short period of time.

Abstract: Ring configuration dye laser capable of supporting laser oscillations in the form of backward and forward running waves and including unidirectional polarization shifter for causing preferential oscillation of one of said waves in unidirectional, single frequency operation.