Abstract: High-power excimer lasers are assembled with individually replaceable optical module subsystems containing consumable optical components. Windows formed in the enclosures of the optical modules incorporate a fluorescent material for converting ultraviolet light scattered from the components of the optical module into visible light emanating from the windows. Changes in the amount or location of the visible light emanating from the windows are interpreted as indications of the degradation in the performance of the optical modules.

Abstract: The invention is directed to single crystal alkaline earth metal fluoride optical elements having an adhesive, hermetic coating thereon, the coating being chemically bonded to the surface of the metal fluoride optical element with a bonding energy ?4 eV and not merely bonded by van de Walls forces. The materials that can be used for coating the optical elements are selected from the group consisting of SiO2, F—SiO2, Al2O3, F—Al2O3, SiON, HfO2, Si3N4, TiO2 and ZrO2, and mixtures (of any composition) of the forgoing, for example, SiO2;HfO2 and F—SiO2/ZrO2. The preferred alkali earth metal fluoride used for the optical elements is CaF2. Preferred coatings are SiO2, F—SiO2, SiO2/ZrO2 and F—SiO2/ZrO2.

Abstract: A crystal optical material is illuminated at a wavelength of light that does not ionize the crystal optical material. Birefringence is measured between a plurality of voxels within the crystal optical material having spatial dimensions small enough to distinguish optical propagations of the light encountering boundary regions between subgrains of the crystal mosaic from optical propagations of the light through the subgrains themselves. The measured birefringence is evaluated for quantifying a characteristic of the crystal matrix. Metrics describing the crystal matrix are associated with performance of the crystal optical material.

Abstract: The invention is directed to optical elements that are coated with dense homogeneous fluoride films and to a method of making such coated elements. The coatings materials are a high (“H”) refractive index fluoride material and a low (“L”) refractive index material that are co-evaporated to form a coating layer of a L-H coating material (a co-deposited coating of L and H materials). Lanthanide metal fluorides (for example, neodymium, lanthanum, dysprosium, yttrium and gadolinium, and combinations thereof) are preferred metal fluorides for use as the high refractive index materials with lanthanum fluoride (LaF3) and gadolinium fluoride (GdF3) being particularly preferred. Aluminum fluoride (AlF3) and alkaline earth metal fluorides (fluorides of calcium, magnesium, barium and strontium) are the preferred low refractive index materials, with magnesium fluoride (MgF2) being a preferred alkaline earth metal fluoride.

Abstract: The invention is directed to a method for cleaning surfaces of optical elements made from metal fluoride single crystals of formula MF2, where M is calcium, barium, magnesium, or strontium, or mixtures of the foregoing, prior to coating the elements with films of protective materials; and to a DUV optic made using the foregoing method. The method has at least the steps of: (a) immersing the optical element in at least one selected liquid and utilizing sonication at megasonic frequencies to remove particulates, polishing slurry residue and the damaged top layer of the optical element; (b) cleaning in a gas phase cleaning process whereby hydrocarbons are removed from the surface of the optical element using UV/ozone cleaning; and (c) exposing, in a gas phase process, of the optical element's surface to a low-energy plasma containing argon and oxygen, xenon and oxygen, or fluorine in a vacuum environment.

Abstract: The invention is directed to elements having fluoride coated surfaces having multiple layers of fluoride material coatings for use in laser systems, and in particular in laser systems operating at wavelength <200 nm. In a particular embodiment the invention is directed to highly reflective mirrors for use in wavelengths <200 nm laser systems. The invention describes the mirrors and a method of making them that utilizes a plurality of periods of fluoride coatings, each period comprising one layer a high refractive index fluoride material and one layer low refractive index fluoride material, and additionally at least one layer of an amorphous silica material. The silica material can be inserted between each period, inserted between a stack consisting of a plurality of periods, and, optionally, can also be applied as the final layer of the finished element to protect the element.

Abstract: A laser beam is generated and transmitted within an enclosed pathway through at least one crystal optic at a power density that progressively degrades transmissivity of the crystal optic with accumulating fluence. The crystal optics are cooled below normal operating temperatures to slow the progressive degradation in the transmissivity of the crystal optics with the accumulating fluence or to accommodate a higher power density without correspondingly increasing the progressive degradation in transmissivity.

Abstract: A crystal optical material is illuminated at a wavelength of light that does not ionize the crystal optical material. Birefringence is measured between a plurality of voxels within the crystal optical material having spatial dimensions small enough to distinguish optical propagations of the light encountering boundary regions between subgrains of the crystal mosaic from optical propagations of the light through the subgrains themselves. The measured birefringence is evaluated for quantifying a characteristic of the crystal matrix. Metrics describing the crystal matrix are associated with performance of the crystal optical material.

Abstract: The present invention relates to optical systems, beam expanding assemblies, line narrowing modules, and lasers having refractive optical elements with wavefront correcting optical surfaces. The present invention enables the skilled artisan to provide optical systems, beam expanding assemblies, line narrowing modules, and lasers having improved optical properties, such as, in the case of lasers, narrow linewidth at high power, and substantially planar wavefronts.

Abstract: The present invention relates to optical systems, beam expanding assemblies, line narrowing modules, and lasers having refractive optical elements with wavefront correcting optical surfaces. The present invention enables the skilled artisan to provide optical systems, beam expanding assemblies, line narrowing modules, and lasers having improved optical properties, such as, in the case of lasers, narrow linewidth at high power, and substantially planar wavefronts.

Abstract: Crystallized ammonium thiosulfate is manufactured by converting ammonia with oxygen containing sulfur dioxide in ammonium thiosulfate solution to ammonium bisulfite and ammonium sulfite in a first step, while maintaining a pH of from 5.5 to 7.0 and a reaction temperature of up to 80.degree.C. In a second step, the ammonium bisulfite and ammonium sulfite in the solution are converted with ammonia and sulfur to ammonium thiosulfate.