Abstract: When rays of light converge inside a photosensitive material at angles larger than 70 degrees, one polarization of the light may fail to produce the desired image contrast in conventional exposure media. This invention describes means of suppressing the effects of the undesired polarization by using a class of photosensitive media that are insensitive to that polarization and more sensitive to the polarization conveying the desired image contrast as well as by means of optical configurations relevant in the context of semiconductor manufacturing using photolithography.

Abstract: When rays of light converge inside a photosensitive material at angles larger than 70 degrees, one polarization of the light may fail to produce the desired image contrast in conventional exposure media. This invention describes a material which may be applied to a semiconductor wafer surface which ensures that the photosensitive material is exposed principally by light polarized parallel to the semiconductor wafer surface.

Abstract: The interior surfaces of the holes in holey optical fibers has adsorbed optically material which may be detected by propagating laser light down the axis of the fiber and detecting Raman, Infrared, or visible fluorescence or absorption.

Abstract: A photolithography method and apparatus for producing minima of light intensity corresponding to a point in a phase shift mask is described. The phase shift in the light produced by the mask varies in a spiral fashion around the point so that the phase shift measured along lines drawn across the surface of the mask which pass through the point have a 180° jump at the point, and lines passing around the point have no jumps between 130° and 230°, and most preferably no jumps between 100° and 260°.

Abstract: A photolithography method and apparatus for producing minima of light intensity corresponding to a point in a phase shift mask is described. The phase shift in the light produced by the mask varies in a spiral fashion around the point so that the phase shift measured along lines drawn across the surface of the mask which pass through the point have a 180° jump at the point, and lines passing around the point have no jumps between 130° and 230°, and most preferably no jumps between 100° and 260°.

Abstract: A diffusion barrier attached to the cladding layer prevents significant diffusion of a Raman active gas out of the holes in a holey fiber or photonic band gap fiber.

Abstract: Hollow core or “holey” optical fibers are filled with a gas or liquid which exhibits high Raman gain. Such gases as hydrogen and hydrogen isotopes are preferred embodiment. When these fibers are pumped with a pump laser, signals at an appropriate frequency carried by the fiber may be amplified, attenuated, changed to a different frequency, or mixed with other signals.

Abstract: The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180° shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.

Abstract: The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180° shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.

Abstract: The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180° shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.

Abstract: The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180° shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.

Abstract: A non-linear crystal is used as an optical radiation frequency converter. Its efficiency is optimized though control of one or more operating conditions that include the temperature of the crystal, its angular relationship with incident radiation and an electric field bias in which the crystal operates. The relative phase between radiation incident upon the crystal and that generated by it is adjusted by a servo loop which controls one or more of these operating conditions. The servo loop responds to a cyclic variation in the output radiation which occurs when the crystal is not operating at an optimal efficiency. A quasi-phase matched (QPM) crystal is preferred. Several specific crystal structures are described. The technique has an application in a frequency doubler, among others.