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

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.