Invisibility of a finite dielectric cylinder under Fano resonance conditions

The effect of invisibility of a finite homogeneous dielectric cylinder due to a substantial decrease in the scattering of electromagnetic waves in specific spectral ranges has been investigated theoretically. A regime of invisibility of the cylinder in an air space without additional cloaking devices has been considered. The effect is based on the resonance suppression of scattered waves, which makes the cylinder invisible to an observer located at any point of the space. The invisibility condition is determined by the Fano resonance between the re-emitted Mie modes and the nonresonant scattering by the cylinder. The dependence of the spectra of the total scattering cross section on the ratio between the length and radius of the cylinder has been analyzed in detail. It has been shown that the transition from the model infinite cylinder to the cylinder of finite length is accompanied by the appearance of new resonances and additional scattering, which, however, does not disturb the lowest frequency region of invisibility at specific length-to-radius ratios of the cylinder.