United States of America As Represented by the Secretary of the Air Force

Dennis C Duneman

Richard A Carreras

James M Wilkes

Dan K Marker

James R Rotge

Joseph M Geary

Janet S Fender

Raymond V Wick

Christopher R DeHainaut

David F Holmes

Charles E Moeller

John D Gonglewski

Sergio Restaino

Gordon D Love

Ronald L Sessions

Morten Jenks

Darius S Vunck

An optical quality, freestanding, compliant membrane mirror is cast with a concave parabolic shape, and includes a substrate and a reflective stress coating. The stress coating is in compression and applies a tensile shear stress to the substrate that opposes and offsets the intrinsic stress in the substrate that would otherwise decrease the concavity. The stress coating generates a force to restore the membrane mirror to its cast concave parabolic shape when an external force deforms the mirror.

Parabolic membrane mirror having a shape-restorative force

A method for fabricating an optical quality, free-standing, compliant parabolic membrane mirror using an inverted parabolic mandrel created by rotating a liquid confined to a cylindrical polymer and applying a reflective optical stress coating once the substrate has hardened. The stress coating applies a tensile force to the substrate that offsets the stress in the substrate that would otherwise decrease the convexity, and also generates a force to restore the membrane mirror to its original convex parabolic shape when the mirror is deformed by an external force.

Method of centrifugally casting a parabolic membrane mirror having a shape-restorative force

A membrane mirror having an optical quality spherical shape maintained by differential pressure takes a near parabolic shape when a plunger-induced displacement of the central area of the mirror is introduced. The focal length can be adjusted by varying the differential pressure.

Plunger controlled, near-parabolic optical membrane mirror

A thin membrane is mounted on an optically flat circular outer ring and stretched over a smaller optically flat circular inner ring. Differential pressure is applied to the annulus formed between the inner and outer rings to prestrain the membrane and separately applied to the inner ring where the mirror figure will be produced. The inner ring has a doubly curved top surface and is optically fiat so that the membrane can freely move across the inner ring as incremental stress is applied via the annulus. A calculated combination of annulus stress and differential pressure on the inner ring produces an optical quality mirror figure in the inner ring area.

Active edge controlled optical quality membrane mirror

Large space-based optical systems are expected to produce optical beams with large wavefront phase aberrations due to their size, weight limitations, optical misaligments and primary mirror imperfections. The present invention combines a phase diversity wavefront sensor with a real-time programmable two-dimensional array of liquid crystal variable retarders for wavefront correction.

Liquid crystal active optics correction for large space based optical

An electrooptical sensor system directly measures the angle between two nearly parallel collimated laser beams. After focussing with a positive lens, the beams pass through a photoelastic modulator, a quarter wave retardation plate, and two polarizers. The beams then hit a lateral cell position sensor. Electrical signals from the lateral cell are processed with special electronics to yield a voltage which is proportional to the angular difference between the two beams. The sensor measures extremely small angles and operates at a high bandwidth. Its primary application is in the control of phased array optical telescopes.

Optical differential tilt sensor

A method of photographically recording at high speed the far field pattern of a high energy infrared laser beam over a selected period of time for providing rapid repetitive samples of information on beam parameters such as far field beam intensity, jitter, and absolute beam size and power. A sample from a high energy infrared laser beam is directed into an enclosure that is light tight to visible radiation and contains an operating lensless movie camera loaded with suitable movie film. The infrared beam is focused on the film plane of the camera so that consecutive frames of the film are irradiated by the infrared beam each time the camera shutter is open. The period of irradiation is of sufficient duration to sensitize the film to visible radiation in the areas where the infrared radiation impinges on the film. The position of the camera shutter is detected and an electrical trigger signal generated just before the shutter is closed for each frame. The trigger signal is applied to appropriate circuitry which actuates a light source to generate a pulse of visible light that irradiates the film plane of the camera near the end of each shutter movement to expose each frame of the film. The exposed film strip is developed to provide a continuous record of the infrared laser beam characteristics over the selected period of time.

Growing community of inventors

Albuquerque, NM, United States of America

Dennis C Duneman