Numerical analysis of optical super-resolution in a structure of quasi-Luneburg-sphere

摘要

Luneburg-sphere (LS) is a spherically symmetric sphere with three-dimensional graded-refractive-index structure which can focus parallel beam to a perfect point on the sphere surface. Recent research shows that microsphere can generate super-resolution focusing beyond diffraction limit. Herein a quasi-Luneburg-lens can be used as an optically transparent microsphere for the super-resolution imaging. In this paper, the finite element model is used to investigate the optical properties of the Luneburg-lens. Our simulation results demonstrated that its focus size is below the conventional diffractive limit in the visible spectrum. An effective method of application of a quasi-Luneburg-lens is proposed and discussed. Besides super-resolution imaging, Luneburg-lens have the potential applications in nanolithography, nanomedicine areas as well.