Abstract: A moisture sensitive optically nonlinear crystal is enclosed in a hermetically sealed elongated vacuum cell. The vacuum cell has an input window at one end and an output window at an opposite end providing optical access to the crystal by a laser beam. The windows are attached to the cell by cold-formed, indium-metal ram-seals. In an example of the cell in which the crystal is arranged to generate UV radiation from the laser beam, the output window is located at a sufficient distance from the crystal that the flux of UV radiation incident on the output window is below the damage threshold of the window for the UV radiation.

Abstract: An optical fiber assembly includes a clad optical fiber having an end-cap thereon. Radiation is focused into the optical fiber via the end-cap. A roughened portion of the fiber cladding behind the end-cap allows any radiation focused into the fiber and propagating in the cladding to escape the optical fiber. A concave reflector surrounding the optical fiber reflects the escaped radiation away from the fiber assembly. A connector for connecting the optical fiber to a laser includes an air-cooled beam-dump for receiving the radiation reflected away from the optical fiber.

Abstract: A moisture sensitive optically nonlinear crystal is enclosed in a hermetically sealed elongated vacuum cell. The vacuum cell has an input window at one end and an output window at an opposite end providing optical access to the crystal by a laser beam. The windows are attached to the cell by cold-formed, indium-metal ram-seals. In an example of the cell in which the crystal is arranged to generate UV radiation from the laser beam, the output window is located at a sufficient distance from the crystal that the flux of UV radiation incident on the output window is below the damage threshold of the window for the UV radiation.

Abstract: A truncated triangular prism has an entrance and an exit face perpendicular to each other and a reflecting face inclined at an angle ? to the entrance face where ? is about 135°??B, and where ?B is the external Brewster angle for the material of the prism at the wavelength of radiation to be reflected by the prism. A beam of p-polarized radiation directed into the prism through the entrance face at the Brewster angle is totally internally reflected from the reflecting face and leaves the exit face at the Brewster angle and at an angle of ninety degrees to the direction at which the radiation enters the prism.

Abstract: Negative Group-delay-dispersion mirror (NGDD-mirror) multilayer structures include a generally-orderly arrangement of layers or groups of layers in which the function of certain individual layers or groups of layers can be recognized and defined. The structures are broadly definable as a rear group of layers which are primarily responsible for providing a desired reflection level and reflection bandwidth together with a low and smoothly varying reflection phase-dispersion, and a front group of layers which are primarily responsible for producing high reflection phase-dispersion necessary for providing a desired NGDD level and bandwidth. The front group of layers relies on multiple resonant trapping mechanisms such as two or more effective resonant-cavities, employing one or more sub-quarter-wave layers to shape the phase-dispersion for providing a substantially-constant NGDD.

Abstract: Negative Group-delay-dispersion mirror (NGDD-mirror) multilayer structures include a generally-orderly arrangement of layers or groups of layers in which the function of certain individual layers or groups of layers can be recognized and defined. The structures are broadly definable as a rear group of layers which are primarily responsible for providing a desired reflection level and reflection bandwidth together with a low and smoothly varying reflection phase-dispersion, and a front group of layers which are primarily responsible for producing high reflection phase-dispersion necessary for providing a desired NGDD level and bandwidth. The front group of layers relies on multiple resonant trapping mechanisms such as two or more effective resonant-cavities, employing one or more sub-quarter-wave layers to shape the phase-dispersion for providing a substantially-constant NGDD.