Advances in Science and Technology Vol. 82

Abstract: Until recently, the phrase adaptive optics generally conjured images of large deformable mirrors being integrated into telescopes to compensate for atmospheric turbulence. However, the development of smaller, cheaper devices has sparked interest for other aerospace and commercial applications. Variable focal length lenses, liquid crystal spatial light modulators, tunable filters, phase compensators, polarization compensation, and deformable mirrors are becoming increasingly useful for other imaging applications included guidance navigation and control (GNC), coronagraphs, foveated imaging, situational awareness, autonomous rendezvous and docking, non-mechanical zoom, phase diversity, and enhanced multi-spectral imaging. Active components presented allow flexibility in the optical design, increasing performance. In addition, the intelligent optical systems presented offer advantages in size and weight and radiation tolerance.

Abstract: We report the results of performance of closed-loop adaptive optical systems intended for phase correction of pulsed and cw laser beams. The conventional control of adaptive system is based on wavefront sensing (e.g., Hartmann-Shack) and following deformation of adaptive mirror surface. We demonstrate the results of such static phase correction in the cases of the vortex laser beam and the powerful laser beam of pulsed “Luch” facility. On other side, applying the sensor-less approach we perform the dynamic phase correction of tip-tilts and higher phase aberrations of laser beams using the stochastic parallel gradient algorithm embedded into the special control units with microcontroller that considerably broadens the system operation bandwidth.

Abstract: In the interests of the problem of debris search and detection we present the results of numerical simulation of projection of an outgoing laser beam through turbulent atmosphere onto the rough surface of a debris object using an adaptive mirror. For this purpose we analyze the wavefront vortex structure of the radiation, which is backscattered from the object surface and propagates through the turbulent atmosphere into a receiving aperture. Analysis shows that perfect phase conjugation does not ensure the maximal concentration of outgoing beam power on the object if the topological charge of backscattered radiation differs from zero in the receiving aperture. It is shown that the efficiency of focusing the outgoing laser beam onto the object can be enhanced by special control of a flexible adaptive mirror.