Theoretical Model of Microparticle-Assisted Super-Resolution Microscopy
We present the first three-dimensional theoretical model of microparticle-assisted super-resolution imaging, enabling accurate simulation of virtual image formation. The model reveals that accounting for partial spatial coherence of illumination is a fundamental prerequisite for achieving super-resolution. We also propose a novel illumination strategy based on suppressing the normal component of incident light, which enhances image contrast and resolution. It is shown that as the size of the investigated objects increases, the optical resolution of the microsphere improves. An analytical estimate for the resolution criterion in microsphere-assisted imaging is presented. The results establish a consistent wave-optical framework that reproduces experimentally observed subwavelength imaging and clarifies the underlying physical mechanisms.