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

David F Holmes

Joseph M Geary

Dennis C Duneman

Christopher R DeHainaut

Morten Jenks

John D Gonglewski

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

Real time presentation and evaluation of any selected interferogram is realized by electronically simulating optical aberration patterns and displaying them on a cathode ray tube (CRT). The optical aberration patterns include PISTON; X and Y TILT; DEFOCUS; SPHERICAL; COMA; and ASTIGMATISM. The aberration patterns are generated electronically in response to the CRT beam sweep drive signal and are displayed as a function of CRT beam intensity. Any combination of aberration patterns, each having selectable coefficients, can be displayed. The aberration pattern coefficient values are indicated by a digital readout. Evaluation of an unknown interferogram is accomplished by varying aberration pattern combinations and coefficients until a substantial match with the unknown interferogram is achieved. The contributing aberration patterns are then known and their magnitudes are determined from the digital read-out.

Growing community of inventors

Albuquerque, NM, United States of America

David F Holmes