Accurate Estimation of non-Resonant Far-Field Superresolution by a Glass Microparticle

In this paper, we theoretically study the spatial resolution granted by a glass microsphere to two pointwise dipoles separated by a tiny gap and located on the sphere surface. This resolution is considered via parameters of the so-called virtual sources effectively shaped by the microparticle of the radiation of the real sources. The geometrical optics qualitatively explains these virtual sources, but only full-wave simulations give a reliable information of their location and sizes. We developed a method for finding these sources from COMSOL simulations. The virtual source is defined as the waist of the wave beam obtained from the imaging beam by its exact inversion performed at a very large distance from the microparticle. We have obtained both pessimistic and optimistic estimates for the ultimate resolution. We found that the novel scenario of the microparticle imaging theoretically revealed in our previous work, promises much finer resolution than the conventional scenario.