Scenarios of non-resonant far-field subwavelength imaging by a simple glass microsphere

Abstract

A hypothesis that a simple glass microsphere excited by a point dipole located on its surface or in its close proximity creates an imaging beam in some sense similar to that created by a metamaterial hyperlens found the confirmation in our numerical simulations. The imaging beam can be created either by creeping waves or simply by rays emitted by the object refracting on the back side of the sphere. The first mechanism of imaging can be implemented by glass microspheres of modest sizes, corresponds to the coherent imaging and demands the lateral coherent illumination. The second and most important mechanism can be implemented by microspheres of larger sizes. It corresponds to the non-coherent non-resonant imaging. In this case we envisage several scenarios of the imaging. One of them corresponds to the case experimentally implemented by the group of M. Hong in 2011, and other scenarios still need an experimental check. In our COMSOL simulations we checked these scenarios partially, but one of them was implemented completely and the resolution about λ/4 in far fields was numerically demonstrated.