Far-field detection of the super-lensing effect in the mid-infrared: theory and experiment

Super-lensing is an electromagnetic phenomenon, based on the amplification of evanescent waves, capable of increasing the resolution of an optical imaging device beyond the diffraction limit. A multi-layer planar super-lens can be constructed from two materials: one with a negative dielectric permittivity epsilon < 0 inserted between two slabs of another material with a positive dielectric permittivity epsilon(d) = -epsilon > 0. We numerically modelled and experimentally implemented a super-lens in the mid-infrared spectral range (around 11 mm) by creating a three-layered structure of submicron thickness, SiO2/ SiC/ SiO2, in which the polaritonic material SiC has a negative dielectric permittivity in the restrahlen band between the frequencies of the transverse and longitudinal optical phonons. A far-field diagnostic of super-lensing based on measuring transmission and reflection coefficients through the metal-coated super-lens has been implemented using a tunable CO2 laser.