Litton Systems, Inc.

Anthony W Louderback

Alan F Stewart

Samuel Lu

Ming-Jau Sun

David T Wei

A mirror for reflecting a selected frequency of light includes a plurality of alternating quarter wavelength thick layers of two dielectric materials that are resistive to physical and chemical changes upon exposure to ultraviolet radiation coated upon a substrate. The materials have different refractive indices. The materials preferably are comprised of a mixture of alumina and tantala as the high refractive index layer and alumina as the low refractive index layer.

Ultraviolet resistive coated mirror and method of fabrication

A coating for an optical component is formed to be antireflective for a selected wavelength and resistive to the transmission of ultraviolet radiation. The coating has first layer is formed of a dielectric material having a refractive index n.sub.1 coated onto the optical component. A second layer is formed of a dielectric layer having a refractive index n.sub.2 that is smaller than the refractive index n.sub.1 of the first layer. The second layer is formed of a material that transmits the selected wavelength while blocking ultraviolet light, thereby protecting the first layer and the optical component from damage due to exposure to ultraviolet radiation. The thicknesses of the layers is selected so that the coating is antireflective for the selected wavelength.

Ultraviolet resistive antireflective coating of Ta.sub.2 O.sub.5 doped

There is disclosed a device for measuring total diffuse optical scattering from the surface of a sample, including a surface having extremely low scatter. A light beam from a laser is directed through an entrance hole in an ellipsoidal reflector and through the vicinity of a first focus of the reflector. The reflector has a first aperture adjacent the first focus for receiving a sample to be measured and a second aperture adjacent a second focus for receiving a photoresponsive means. A sample mounting means is used to position the sample at the first focus and to orient the sample so that the portion of the light beam which is specularly reflected from the sample is directed out of an exit hole located in the reflector diametrically opposite to the entrance hole. A major portion of the light diffusely scattered from the sample into a 2.pi. solid angle (hemisphere) reaches the second aperture either directly or by a single reflection from the reflector. The photoresponsive means such as a photomultiplier is positioned at the second aperture for detecting the magnitude of light scattered. In a specific embodiment, the ellipsoidal reflector is easily and cheaply made from two half-ellipsoidal mirrors which are joined together at their wide ends.

Device for measurement of optical scattering

A method for fabricating multiple layer interference optical films by ion beam sputtering, said films being used for mirrors in a ring laser apparatus. An ion beam strikes a target material obliquely, dislodging molecules of the target so that they can be deposited on a surface serving as a base for a multiple layer interference coating. The thickness of the coating is monitored so that the proper thickness of a given layer can be optimized to obtain the type of reflectance desired for a given light wave length. The surface to be coated is rotated during the deposition of the layer of target material. A stack of layers of alternating indices of refraction comprises the optical interference film. The coating process occurs inside of a vacuum chamber where the partial pressures of the gases are carefully controlled to insure the proper ion beam intensity and optimum stoichiometry of the deposited optical films. Prior to beginning the deposition of optical films, the ceramic substrate comprising the mirror base is bombarded by the ion beam at an oblique angle to remove surface anomalies and clean it.

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Eugene, OR, United States of America

Anthony W Louderback