N131-076 TITLE: Advanced Adaptive Optics (AO) for Laser Weapons in Heavy Turbulence

TECHNOLOGY AREAS: Sensors, Weapons

OBJECTIVE: Develop a beaconless adaptive optic system capable of correcting moderate to heavy atmospheric distortion of the high-power laser beam in laser weapon systems.

DESCRIPTION: Adaptive Optics (AO) are used routinely in astronomical telescopes for correction of atmospheric distortion. More recently, adaptive optics have been implemented on laser weapon systems including the Airborne Laser. However, both of these applications require a reference source for measurement of the atmospheric distortion. In the case of astronomical telescopes this can be either a natural or artificial star. For the Airborne Laser a beacon illuminator laser was used. This beacon laser complicates the optical path and adds cost and complexity to the system.

For future laser weapon systems we seek to develop a beaconless adaptive optic system capable of correcting moderate to heavy atmospheric distortion of the high power laser beam. There are most likely several possible approaches to this solution. One possible approach may be to utilize the High-Energy Laser (HEL) as a source to extract information from the target image which can be used to provide beam control corrections. Other possible optical techniques may utilize characterization of the laser beam distortion or statistics of the atmospheric turbulence. If you were to use the HEL technology in your approach, challenges will include avoidance of stray light from the HEL and speed of response of the AO system as well as aberration measurement and compensation. The proposed system should demonstrate near diffraction target imagery for targeting in deep turbulence conditions (Rytov >.3), wavefront aberration determination to a tenth wave at 1 micron, and wavefront correction through the AO system to a tenth wave.

PHASE I: Develop theoretical analysis and design of the system modeling and simulation indicating beaconless imaging, aberration metrology, and level of compensation achieved. The proof-of-concept prototype system should obtain as a goal a tenth wave aberration measurement and compensation ability in a Rytov >.3 turbulence condition.

PHASE II: Prepare and test the prototype in a laboratory and verify level of performance. The system should obtain as a goal a tenth wave aberration measurement and compensation ability in a Rytov >.3 turbulence condition.

PHASE III: Demonstrate developmental system with field testing and performance verification.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This SBIR topic will have applications to all imaging and telescope systems such as astronomy, space surveillance, Light Detection and Ranging (LIDAR), and communications which are limited in resolution by atmospheric turbulence. These systems can benefit from a beaconless guide star and atmospheric compensation technology.

REFERENCES:
1. Hardy, John W. 1998. Adaptive Optics for Astronomical Telescopes USA: Oxford University Press.

2. Booth, Martin J. 2006. "Wave Front Sensorless Adaptive Optics: A Model-based Approach
Using Sphere Packings." Optics Express, Vol. 14, Issue 41339–1352.http://dx.doi.org/10.1364/OE.14.001339.

3. Vorontsov, Mikhail A. and Kolosov, V. 2005. "Target-in-the-Loop Beam Control: Basic Considerations for Analysis and Wave-Front Sensing." Journal of the Optical Society of America A. 22, 126–141. PMID: 15669623.

4. Weyrauch, Thomas, Mikhail A. Vorontsov, Thomas G. Bifano, Jay A. Hammer, Marc Cohen
and Gert Cauwenberghs. 2001. "Microscale Adaptive Optics: Wave-Front Control with a u-Mirror
Array and a VLSI Stochastic Gradient Descent Controller." Applied Optics. 40, No. 24 4243–
4253. http://dx.doi.org/10.1364/AO.40.004243.

5. Roggemann, Michael C. and William R. Reynolds. 2002. "Block Matching Algorithm
for Mitigating Aliasing Effects in Undersampled Image Sequences," Optical Engineering. 41, 359–369. DOI: 10.1117/1.1431250.

KEYWORDS: Laser beacon; guide star; high-energy laser; adaptive optics; atmospheric turbulence compensation

** TOPIC AUTHOR (TPOC) **

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