CC BY
12P-III
Optical Phenomena in Micrometer Dielectric Spheres
B.S. Lukiyanchuk
Faculty of Physics, Lomonosov Moscow State University lukiyanchuk@nanolab. phys. msu.ru
In the Mie theory, representing the exact solution of Maxwell's equations for scattering plane wave on a homogeneous sphere, electromagnetic fields depend on the refractive index of the sphere, n, and the so-called size parameter, q = 2nR / X, where R is the radius sphere, and X is the radiation wavelength. The history of classical optics is associated with lenses, with a size of about one centimeter (Galileo's telescope, microscope, etc.). The corresponding size parameter in such optical systems is quite large, q > 105. The geometrical optics approximation is in good agreement with the Mie theory for q > 102. Research on the optics of nanostructures in plasmonics and nanophotonics refer to the systems where the size parameter is of the order of unity, q ~ 1. In this area, progress has been made in the study of optically resonant dielectric nanostructures with a high refractive index [1]. At the same time, structures with the size parameter of the ten, q ~ 10, are in the region between the wave and geometric optics turned out to be a "blank spot" on the map of optics due to the reason that lenses of the size of a few micrometers had no particular interest.
However, the studies on the optics of dielectric spheres micrometer sizes over the past twenty years, discover a number of unusual phenomena, including photonic nanojets [2], optical nanovortices [3], Fano resonances [4], magnetic light [5], the effects of overcoming the diffraction limit in the virtual image [6], effects associated with the excitation of anapole modes [7-9] and the excitation of giant magnetic fields [10]. The report gives an overview of these phenomena and discusses the physical mechanisms underlying these phenomena. The presence of a number of interesting applications indicates a new promising direction in optics.
This work was supported by the Ministry of Science and Higher Education Russian Federation (grant № 14.W03.31.0008) and also partially supported by the Russian Science Foundation (project № 20-1200389) and by the Basic Russian Foundation (project № 20-02-00715).
References
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8. B. Lukyanchuk et al.// Phil. Trans. Roy. Soc. A 375, 20160069 (2017).
9. B. Luk yanchuk et al.// Phys. Rev. A 95, 063820 (2017).
10. Z.B. Wang et al.// Scientific Reports 9, 20293 (2019).
