Toward Defeating Diffraction and Randomness for Laser Beam Propagation in Turbulent Atmosphere

• Published in: JETP letters Vol. 108; no. 9; pp. 571 - 576
• Main Authors: Lushnikov, P. M., Vladimirova, N.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.11.2018; Springer Nature B.V
• Subjects: Atomic; Biological and Medical Physics; Biophysics; Collimation; Diffraction; Disintegration; Electric power; Electricity generation; Gaussian beams (optics); Irradiance; Laser beams; Lasers; Molecular; Optical and Plasma Physics; Optics and Laser Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Propagation; Pulsed lasers; Quantum Information Technology; Solid State Physics; Spintronics
• ISSN: 0021-3640; 1090-6487
• DOI: 10.1134/S0021364018210026

A large distance propagation in turbulent atmosphere results in disintegration of laser beam into speckles. We find that the most intense speckle approximately preserves both the Gaussian shape and the diameter of the initial collimated beam while loosing energy during propagation. One per 1000 of atmospheric realizations produces at 7 km distance an intense speckle above 28% of the initial power. Such optimal realizations create effective extended lenses focusing the intense speckle beyond the diffraction limit of vacuum propagation. Atmospheric realizations change every several milliseconds. We propose to use intense speckles to greatly increase the time-averaged power delivery to the target plane by triggering the pulsed laser operations only at times of optimal realizations. Resulting power delivery and laser irradiance at the intense speckles well exceeds both intensity of diffraction-limited beam and intensity averaged over typical realizations.