Open AccessLaser beam focusing through a moderately scattering medium using a bimorph mirror
Author(s) -
Ilya Galaktionov,
Julia Sheldakova,
Alexander Nikitin,
Vadim Samarkin,
В. А. Парфенов,
Alexis Kudryashov
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.408899
Subject(s) - optics , scattering , bimorph , materials science , laser , deformable mirror , numerical aperture , beam (structure) , focal length , brightness , forward scatter , aperture (computer memory) , light scattering , physics , wavefront , wavelength , lens (geology) , piezoelectricity , acoustics , composite material
The rarely considered case when the optical radiation passes through the weakly scattering medium, e.g. mid-density atmospheric fog with the number of scattering events up to 10 was investigated in this paper. We demonstrated an improvement of focusing of a laser beam (λ=0.65 µm) passed through the 5 mm-thick layer of scattering suspension of 1 µm polystyrene microbeads diluted in a distilled water. For the first time the low-order aberration corrector - wide aperture bimorph deformable mirror with 48 electrodes configured in 6 rings was used to optimize a far-field focal spot. We compared efficiencies of the algorithm that optimized the positions of the focal spots on Shack-Hartmann type sensor and the algorithm that optimized the peak brightness and the diameter of the far-field focal spot registered with a CCD. We experimentally demonstrated the increase of the peak brightness of the far-field focal spot by up to 60% due to the use of the bimorph deformable mirror for beam focusing through the scattering medium with concentration values of scatterers ranged from 10 5 to 10 6 mm -3 .