We apply a target-in-the-loop strategy to the case of adaptive optics beam control in the presence of strong atmospheric turbulence for air-to-ground directed energy laser applications. Using numerical simulations we show that in the absence of a cooperative beacon to probe the atmosphere it is possible to extract information suitable for effective beam control from images of the speckled and strongly turbulence degraded intensity distribution of the laser energy at the target. We use a closed-loop, single-deformable-mirror adaptive optics system driven by a target-in-the-loop stochastic parallel gradient descent optimization algorithm minimizing a mean-radius performance metric defined on the image of the laser beam intensity distribution formed at the receiver. We show that a relatively low order 25-channel zonal adaptive optical beam control system controlled in this way is capable of achieving a high degree of turbulence compensation with respect to energy concentration if the tilt can be corrected separately.
© 2007 Optical Society of America
Atmospheric and Oceanic Optics
Original Manuscript: February 23, 2007
Revised Manuscript: May 22, 2007
Manuscript Accepted: July 5, 2007
Published: September 19, 2007
Piotr Piatrou and Michael Roggemann, "Beaconless stochastic parallel gradient descent laser beam control: numerical experiments," Appl. Opt. 46, 6831-6842 (2007)