USA As Represented by Secretary of the Navy

Mikhail Kotov

Jasbinder Singh Sanghera

Shyam S Bayya

Daniel Joseph Gibson

Vinh Q Nguyen

Gryphon A Drake

Geoff Chin

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

Manufacturing process for striae-free multicomponent chalcogenide glasses via multiple fining steps

A method for making high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a sealed ampoule with chemical components enclosed inside, a two-zone furnace, a convection heating/mixing step, and multiple fining steps. Initially, the sealed ampoule is oriented vertically within the two-zone furnace and heated to melt the chemical components contained within, and a temperature gradient is created between the top zone and the bottom zone such that the bottom zone has a higher temperature. This temperature gradient causes convection currents within the viscous liquid until it is sufficiently mixed due to the convective flow. Then the temperature gradient is reversed such that the top zone now has a higher temperature and the convective flow ceases. The furnace temperatures are then reduced over a period of time, with holds at multiple temperatures for fining and cooling to form a solid glass.

Manufacturing process for striae-free multicomponent chalcogenide glasses via convection mixing

A method for making a gradient index infrared transmitting optic by thermally treating a preform, where the preform comprises two or more infrared transmitting glasses having different compositions and optical properties, where there is an interface between adjacent glasses, where during the thermal treatment one or more chemical elements from the glasses diffuses through one or more interface resulting in a diffused gradient index optical element comprising a gradient in the chemical element concentration, and where the optical element has a gradient in refractive index and dispersion. Also disclosed is the related infrared transmitting optical element made by this method.

Gradient index infrared transmitting optics and method for making same

The present invention provides a method for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

A method for bonding infrared transmitting glasses into an optical element without interlayer voids by stacking at least two different infrared transmitting glasses inside a vessel where each glass has a different refractive index, a different dispersion, or both, and where the glasses all have similar viscosities, thermal expansion coefficients, and glass transition temperatures; placing a weight on top of the stack; applying a vacuum to the vessel; applying an isostatic pressure of at least 1500 psi; and after releasing the isostatic pressure, annealing at a temperature within 10&#xb0; C. of the glass transition temperature at a pressure between 0 and 1000 psi. Applying the vacuum, applying the isostatic pressure, and annealing are done sequentially and with no intermediate transitions to ambient temperature or pressure. Also disclosed is the related optical element made by this method.

Layered infrared transmitting optical elements and method for making same

A method to synthesize striae-free chalcogenide glass using melt processing. A striae-free chalcogenide glass with uniform refractive index.

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Silver Spring, MD, United States of America

Mikhail Kotov