Dielectric microparticles for enhanced optical imaging: an FDTD analysis of contrast and resolution

Abstract

This paper presents a comprehensive numerical analysis of super-resolution imaging using dielectric microparticles, employing the finite-difference time-domain (FDTD) method to elucidate the mechanisms that enable resolution enhancements beyond the diffraction limit. Our study demonstrates that dielectric microparticles can achieve a resolution of the order of 50 nm in the visible spectrum, surpassing traditional optical microscopy limits. By simulating the propagation of radiation through a microparticle–object system and generating optical images via a backward propagation technique, we reveal critical insights into how microparticles enhance image contrast and resolution. The study also explores the influence of various parameters, such as source coherence and particle–substrate interactions, on the image formation process. Our results not only validate the super-resolution capability of microparticle-assisted imaging but also provide a robust framework for further advancements in optical imaging technologies, with potential applications in fields requiring ultra-high-resolution visualization.