Vorontsov Mikhail A, Kolosov Valeriy V, Polnau Ernst
Intelligent Optics Laboratory, Computational and Information Sciences Directorate, U.S. Army Research Laboratory, Adelphi, Maryland 20783, USA.
Appl Opt. 2009 Jan 1;48(1):A13-29. doi: 10.1364/ao.48.000a13.
Adaptive optical systems for laser beam projection onto an extended target embedded in an optically inhomogeneous medium are considered. A new adaptive optics wavefront control technique--speckle-average (SA) phase conjugation--is introduced. In this technique mitigation of speckle effects related to laser beam scattering off the rough target surface is achieved by measuring the SA wavefront slopes of the target return wave using a conventional Shack-Hartmann wavefront sensor. For statistically representative speckle averaging we consider the generation of an incoherent light source, referred to here as a Collett-Wolf beacon, directly on the target surface using a rapid steering (scanning) auxiliary laser beam. Our numerical simulations and experiment show that control of the outgoing beam phase using SA phase conjugation can lead to efficient compensation of turbulence effects and results in an increase of the projected laser beam power density on a remote extended target. The impact of both target anisoplanatism and the Collett-Wolf beacon size on adaptive system performance is studied.
研究了用于将激光束投射到嵌入光学非均匀介质中的扩展目标上的自适应光学系统。介绍了一种新的自适应光学波前控制技术——散斑平均（SA）相位共轭。在该技术中，通过使用传统的夏克-哈特曼波前传感器测量目标回波的SA波前斜率，实现了与粗糙目标表面激光束散射相关的散斑效应的减轻。为了进行具有统计代表性的散斑平均，我们考虑使用快速转向（扫描）辅助激光束直接在目标表面生成一个非相干光源，这里称为科莱特-沃尔夫信标。我们的数值模拟和实验表明，使用SA相位共轭控制出射光束相位可以有效补偿湍流效应，并导致远程扩展目标上投射激光束功率密度的增加。研究了目标非等晕性和科莱特-沃尔夫信标尺寸对自适应系统性能的影响。
