Formation of the high electromagnetic waves intensity areas by multiple cylinders scattering: whispering gallery modes and photonic nanojet

Abstract

Multiple-cylinder scattering of electromagnetic plane waves are considered. It is shown that the process can led to formation of two kinds of high intensity areas of electromagnetic waves. The first type arise inside cylinder due to so-called whispering gallery modes (WGM), while the second type represents itself a narrow, high-intensity beam of light generated at the shadow-side surface of illuminated dielectric cylinders. In our model, WGM can occur because of the presence of additional cylinder scatterers at specific location, while WGMs can only form in a single cylinder for specific cylinder radius and/or wavelength values. Also, presence of the additional cylinders increases a length of photonic nanojets (up to two times) compared to the case of a single cylinder. The results of calculation for different values of electric permittivity and radii of cylinders are presented and discussed.