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8LM-O-15
Polarization singularities of a plane electromagnetic wave scattered on a dielectric spherical nanoparticle
N. Y. Kuznetsov, K. S. Grigoriev, V. A. Makarov
Faculty of Physics, Moscow State University, Leninskie Gory 1, Moscow 119991, Russia
ny. kuznetcov@physics. msu. ru
Polarization singularities are the regions of the electromagnetic field, where the polarization ellipse of the electric field degenerates to a perfect circle ( Cr-lines) or a line segment (Lr-lines). Distribution of the polariza tion ellipses around these lines is found to be topologically nontrivial, making the singularities persistent under changes of the field parameters [1]. We study the three -dimensional structure of the polarization singularities of a plane monochromatic electromagnetic wave with initially uniform elliptical polarization profile, scattered on a dielectric spherical particle of sub -wavelength radius [2]. For the various values of the incident radiation ellipticity degree we trace thCC1- and Lr-lines of polarization. We discuss existence and geometry of these lines in dependence of the incident radiati ellipticity and complex structures in the distribution of the polarization ellipses, found near their point: We also observe the strips, swept by the axes andnormal vectors of the polarization ellipse being traced along a closed contour, which may form non -orientable surfaces, such as Möbius strips, around the singular lines and classify their behavior.
Fig. 1. A singular pattern and an optical Möbius strip.
We acknowledge financial support from Russian Foundation for Basic Research (19 -02-00069 and 20 -32-90123), Foundation for the Advancement of Theoretical Physics and Mathematics "Basis" and Nonprofit Foundation for the Advancement of Science and Educ ation "Intellect".
[1] J. F. Nye and J. V. Hajnal, The wave structure of monochromatic electromagnetic radiation, Proc. R. Soc. A 409(1836)2 1-36 (1987).
[2] N. Y. Kuznetsov, K. S. Grigoriev, Y. V. Vladimirova, V. A. Makarov, Three-dimensional structure of polarization singularities of a light field near a dielectric spherical nanoparticle, Optics Express. — Vol. 28, no. 19.— P. 27293-27299 (2020).
