Abstract: An illumination system and condenser for use in photolithography in the extreme ultraviolet wavelength region having a first non-imaging optic element collecting electromagnetic radiation from a source and creating a desired irradiance distribution and a second non-imaging optic element receiving the electromagnetic radiation from the first non-imaging optic element and redirecting and imaging the electromagnetic radiation. The electromagnetic radiation emanating from the second non-imaging optic element is suitable for being received by other conventional optical surfaces to provide a desired irradiance distribution with a desired angular distribution and desired shape. Facets are used to provide the desired illumination over the desired illumination field. Reflective facets may be placed on the second non-imaging optic, which can reduce the number of mirrors and increase efficiency.

Abstract: An illumination system and condenser for use in photolithography in the extreme ultraviolet wavelength region having a first non-imaging optic element collecting electromagnetic radiation from a source and creating a desired irradiance distribution and a second non-imaging optic element receiving the electromagnetic radiation from the first non-imaging optic element and redirecting and imaging the electromagnetic radiation. The electromagnetic radiation emanating from the second non-imaging optic element is suitable for being received by other conventional optical surfaces to provide a desired irradiance distribution with a desired angular distribution and desired shape. Facets are used to provide the desired illumination over the desired illumination field. Reflective facets may be placed on the second non-imaging optic, which can reduce the number of mirrors and increase efficiency.

Abstract: An optical system includes multiple cubic crystalline optical elements aligned along a common optical axis and having their crystal lattices oriented with respect to each other to minimize the effects of intrinsic birefringence and produce a system with reduced retardance. The optical system may be a refractive or catadioptric system having a high numerical aperture and using light with a wavelength at or below 248 nanometers. The net retardance of the system is less than the sum of the retardance contributions of the respective optical elements as the elements are oriented such that the intrinsic birefringences of the individual elements cancel each other out. In one embodiment, two [110] cubic crystalline optical elements are clocked with respect to one another and used in conjunction with a [100] cubic crystalline optical element to reduce retardance.

Abstract: A multi-channel optical switching system particularly usable as a programmable optical add/drop multiplexer in a multi-wavelength communication system. The switching system uses a grating operating at Littrow that separates a multi-channel optical signal into a plurality of optical channels, and combines a plurality of optical channels into a multi-channel optical signal. The system also uses a plurality of optical ports optically coupled to the grating and a selecting device to select which optical channel is directed to which of the optical ports.

Abstract: An optical system includes multiple cubic crystalline optical elements and one or more polarization rotators in which the crystal lattices of the cubic crystalline optical elements are oriented with respect to each other to reduce the effects of intrinsic birefringence and produce a system with reduced retardance. The optical system may be a refractive or catadioptric system having a high numerical aperture and using light with a wavelength at or below 248 nanometers. The net retardance of the system is less than the sum of the retardance contributions of the respective optical elements. In one embodiment, all cubic crystalline optical elements are oriented with identical three dimensional cubic crystalline lattice directions, a 90° polarization rotator divides the system into front and rear groups such that the net retardance of the front group is balanced by the net retardance of the rear group.

Abstract: An optical system includes multiple cubic crystalline optical elements and one or more polarization rotators in which the crystal lattices of the cubic crystalline optical elements are oriented with respect to each other to reduce the effects otintrinsic birefringence and produce a system with reduced retardance. The optical system may be a refractive or catadioptric system having a high numerical aperture and using light with a wavelength at or below 248 nanometers. The net retardance of the system is less than the sum of the retardance contributions of the respective optical elements. In one embodiment, all cubic crystalline optical elements are oriented with identical three dimensional cubic crystalline lattice directions, a 90° polarization rotator divides the system into front and rear groups such that the net retardance of the front group is balanced by the net retardance of the rear group.

Abstract: An optical system includes multiple cubic crystalline optical elements and one or more polarization rotators in which the crystal lattices of the cubic crystalline optical elements are oriented with respect to each other to reduce the effects of intrinsic birefringence and produce a system with reduced retardance. The optical system may be a refractive or catadioptric system having a high numerical aperture and using light with a wavelength at or below 248 nanometers. The net retardance of the system is less than the sum of the retardance contributions of the respective optical elements. In one embodiment, all cubic crystalline optical elements are oriented with identical three dimensional cubic crystalline lattice directions, a 90° polarization rotator divides the system into front and rear groups such that the net retardance of the front group is balanced by the net retardance of the rear group.

Abstract: An optical system includes multiple cubic crystalline optical elements and one or more polarization rotators in which the crystal lattices of the cubic crystalline optical elements are oriented with respect to each other to reduce the effects of intrinsic birefringence and produce a system with reduced retardance. The optical system may be a refractive or catadioptric system having a high numerical aperture and using light with a wavelength at or below 248 nanometers. The net retardance of the system is less than the sum of the retardance contributions of the respective optical elements. In one embodiment, all cubic crystalline optical elements are oriented with identical three dimensional cubic crystalline lattice directions, a 90° polarization rotator divides the system into front and rear groups such that the net retardance of the front group is balanced by the net retardance of the rear group.

Abstract: A multi-channel optical switching system particularly usable as a programmable optical add/drop multiplexer (POADM) in a multi-wavelength communication system. The switching system uses a thin film optical demux/mux that separates a multi-channel optical signal into a plurality of optical channels, and combines a plurality of optical channels into a multi-channel optical signal. The system also uses a plurality of optical ports optically connected to the thin film optical demux/mux and a selecting device to select which optical channel is directed to which of the optical ports.

Abstract: An illumination source or condenser used to project the image of a reticle onto a photosensitive substrate used in photolithography having a first reflective fly's eye, faceted mirror, or mirror array with predeterminedly positioned facets or elements and a second reflective fly's eye, faceted mirror, or mirror array having predeterminedly positioned facets or elements for creating a desired radiant intensity, pupil fill, or angular distribution. A source of extreme ultraviolet electromagnetic radiation is provided to a first fly's eye or mirror array with arcuate shaped facets or elements. The arcuate shaped facets or elements are positioned to create an image of the source at corresponding facet in a second reflective fly's eye or mirror array. A desired shape and irradiance together with a desired radiant intensity, pupil fill, or angular distribution is obtained. An arcuate illumination field or image is formed with high efficiency in a compact package.

Abstract: A slag control shape is releasably mounted on a cover for a molten metal vessel. An actuator is connected to a slag control shape release member to retract the release member from a first position engaged with the slag control shape to a second position separated from the slag control shape to allow the slag control shape to freely drop into the molten metal receptacle. The actuating end of the actuator is located at an easily accessible operator position for remote actuation of the release member. In another embodiment, one end of a cable wound in a plurality of turns about a rotatable shaft mounted in a reel is attached to the slag control shape. A spring biasingly engages the shaft to control the rate of rotation of the shaft and thereby the rate of payout of the cable and the rate of descent of the slag control shape into the molten metal vessel.

Abstract: A slag control shape is releasably mounted on a cover for a molten metal vessel. An actuator is connected to a slag control shape release member to move the release member from a first position engaged with the slag control shape to a second position disengaged from the slag control shape to allow the slag control shape to descend into the molten metal vessel. Upon the occurrence of a predetermined condition, such as a predetermined weight of molten metal in the vessel or a predetermined total time of molten metal discharge from the vessel, a controller generates a signal to the actuator to automatically release the slag control shape into the vessel. The controller is located remote from the actuator and transmits the activation signal to the actuator by radio frequency signals, directly through an electrical conductor, or to a light emitter which transmits a light beam to a photodetector mounted on the cover.

Abstract: A slag control shape is releasably mounted on a cover for a molten metal vessel. An actuator is connected to a slag control shape release member to retract the release member from a first position engaged with the slag control shape to a second position separated from the slag control shape allowing the slag control shape to freely drop into the molten metal receptacle. The actuating end of the actuator is located at an easily accessible operator position for remote actuation of the release member. In one embodiment, the actuator is a flexible cable attached at one end to the release member mounted on the cover and having a second end located remote from the cover at an easily accessible operator position. In another embodiment, one end of a cable wound in a plurality of turns about a rotatable shaft mounted in a reel is attached to the slag control shape.

Abstract: A slag control shape is releasably mounted on a cover for a molten metal vessel. An actuator is connected to a slag control shape release member to retract the release member from a first position engaged with the slag control shape to a second position separated from the slag control shape allowing the slag control shape to freely drop into the molten metal receptacle. The actuating end of the actuator is located at an easily accessible operator position for remote actuation of the release member. In one embodiment, the actuator is a flexible cable attached at one end to the release member mounted on the cover and having a second end located remote from the cover at an easily accessible operator position. In another embodiment, a pair of eccentric cams are mounted on the cover and the molten metal receptacle and pivot into engagement upon a downward force exerted on the actuator cable to retract the release member from engagement with the slag control shape.

Abstract: An anti-slag, anti-vortex tundish measurement apparatus for use in tundishes or other molten metal receptacles provides a measurement of the depth of the molten metal layer above the bottom of such receptacles. The apparatus includes a body mounted on a first end of an elongated rod. The body and the rod are formed of a suitable material and have a predetermined size such that the specific gravity of the body and the rod is less than the specific gravity of the molten metal in the receptacle; but greater than the specific gravity of the slag layer covering the top of the molten metal layer such that the body is buoyantly supported at the interface between the slag layer and the molten metal layer. Measurement indicia in the form of incrementally spaced, scale gradations is formed on the second end of the rod, which end extends externally from the interior of the molten metal receptacle.