Adaptive optics is a method whereby we can 'clean up' a laser beam or images to remove effects of atmospheric distortion

http://www.af.mil/news/story.asp?id=123124670

 U.S. AIR FORCE ACADEMY, Colo. (AFNS) – A U.S. Air Force Academy Laser and Optics Research Center physicist received a second patent in less than two months Nov. 18. 

Dr. Geoff Andersen’s newest patent is for the Holographic Adaptive Optic System, and the total number of patents he has earned since beginning his 12-year tenure at the Academy now stands at four. 

“Adaptive optics is a method whereby we can ‘clean up’ a laser beam or images to remove effects of atmospheric distortion,” Dr. Andersen said. 

The new device can be used for correcting the blurring of objects when viewed through atmospheric turbulence either in astronomy or surveillance applications. Alternatively, the system can correct for distortions in laser beams transmitted across large distances. Dr. Andersen’s work has many applications including surveillance, improving the effectiveness of the Air Force’s airborne laser, and in furthering the development of next generation free-space optical interconnects such as laser communications from ground to air and space. 

This new holographic process involves first sensing distortions present in the beam and then applying the inverse aberration to some optic such as a deformable rubber mirror. The concept, developed by Air Force officials, is now used routinely in surveillance, astronomy and eye surgery. However, while the concept is relatively simple, the optics, electronics and computing requirements are often quite exotic and expensive. 

Dr. Andersen’s method for using a multiplexed hologram in conjunction with deformable optics simplifies adaptive optics systems. Holograms can be used to store lots of information accessible in an all-optical parallel processing method, making them very efficient and fast at complex calculations. 

“In this system we encode the hologram with all the possible response functions of a multi-element deformable optic. When we pass light though our system we can then use the combined hologram and deformable optic to correct for distortions in the light,” Dr. Andersen said. “The process is many times faster than existing systems while being much more compact. As a bonus the device removes the need for any computations and is thus much cheaper than current systems.” 

The project was jointly funded by the Air Force Office of Scientific Research and the Air Force Joint Technology Office. 

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