A LABORATORY MODEL OF AN ADAPTIVE OPTICAL SYSTEM, COMPRISING AN ATMOSPHERIC TURBULENCE GENERATOR AND A SYSTEM FOR CORRECTING THE INDUCED PHASE FLUCTUATIONS

Atmospheric turbulence causes distortions in the wavefront of propagating optical radiation. This leads to a degradation of image resolution in astronomical telescopes and significantly reduces the power density of radiation on the target when focusing. The influence of turbulent fluctuations on the wavefront can be studied in laboratory conditions using a deformable mirror as a phase fluctuations generator and a wavefront sensor as a distortion measurer. We have developed a software simulator and an experimental setup for
generating atmospheric turbulence phase fluctuations, as well as an adaptive optical system to compensate for the induced aberrations. Both systems use 60-mm diameter bimorph deformable mirrors with 92 control channels and two tip-tilt correctors. The wavefront is measured using a high-speed Shack-Hartmann wavefront sensor based on an industrial CMOS camera. The system achieved a correction frequency of 600 Hz, reducing the aberration amplitude from 2.6 μm to 0.3 μm during the correction process. The
application of the tip-tilt corrector reduced the range of focal spot centroid jitter by a factor of 2–3.