Abstract: A continuous vent for an endoscope which always allows flow of gas in order to prevent damaging differential pressures and always prevents entry of liquid into the endoscope. A barrier for this purpose overlays a vent port and is held in place by a ring-shaped spacer which with an overhanging shoulder leaves a limited space for flow of fluid and excludes most particulates from the barrier. The barrier maybe an assortment of hydrophobic and hydrophilic layers.

Abstract: An electromagnetic radiation source, such as an arc lamp, is located at a point displaced from the optical axis of a concave toroidal reflecting surface. The concave primary reflector focuses the radiation from the source at an off-axis image point that is displaced from the optical axis. The use of a toroidal reflecting surface enhances the collection efficiency into a small target, such as an optical fiber, relative to a spherical reflecting surface by substantially reducing aberrations caused by the off-axis geometry. A second concave reflector is placed opposite to the first reflector to enhance further the total flux collected by a small target.

Abstract: An off-axis optical system for collecting and condensing electromagnetic radiation utilizes an ellipsoidal reflector or a portion thereof configured so that the effects of magnification and optical aberrations (caused by the off-axis arrangement and an aspherical source envelope) are minimized. This is accomplished by the utilization of a specially designed ellipsoidal reflector having primary and secondary focal points along the major axis of the reflector or an effective reflecting portion thereof defined as that portion which is both illuminated by the source and subtended by the acceptance cone of the target.

Abstract: Apparatus and method for spectroscopic analysis of scattering media. Subtle differences in materials have been found to be detectable from plots of intensity as a function of wavelength of collected emitted and scattered light versus wavelength of excitation light.

Abstract: Experimental studies of a nonlinear interface have indicated that saturation of the nonlinear refractive index may play a critical role in controlling the transition from total internal reflection to nearly total transmission. Numerical simulations of the behavior of a saturated nonlinear interface confirm that saturation effects can dramatically improve transmitted beam shape and switching quality.

Abstract: An optical integration technique using thin film technology is based on a nonlinear interface with a diffusive or saturated Kerr-like nonlinearity. Solid state multiplexing is implemented with thin film multilayer stacks resulting in polarizers and phase retarders matched to the interface. The simplicity of the integration architecture is demonstrated by designing a thin film half-adder, a full adder and a carry-propagate adder.