Vol. 38, issue 12, article # 2

Abstract:

This work is devoted to the development and experimental verification of effective methods for compensating for the dynamic atmospheric distortions of a laser beam propagating through a turbulent medium. The paper presents the results of a laboratory experiment on the correction of wavefront distortions of laser radiation propagating along a turbulent path in a pavilion. Turbulence was simulated using a fan heater supplying warm air perpendicular to the beam propagation. Distortion compensation was performed using an adaptive optics system, including a wavefront tilt corrector and a bimorph deformable mirror. The system efficiency was assessed by analyzing the far-field intensity distribution. It is shown that the generated turbulent distortions are spectrally similar to Kolmogorov turbulence with a bandwidth of about 30 Hz. It is found that for effective compensation of wavefront aberrations, the operating frequency of the adaptive optics system should be 20–30 times higher than the turbulence bandwidth. At a system operating frequency of 1 kHz, the beam divergence was reduced to 1.4 of the diffraction limit, and by increasing the frequency to 2 kHz, a beam stabilization accuracy of 5 mrad can be achieved using an FPGA. The results of this work can be used to design high-performance systems related to the propagation of laser radiation in a turbulent medium.

Keywords:

adaptive optics, adaptive optics system, field programmable gate array, atmospheric turbulence

Figures:

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