Super-resolution hyperspectral characterisation of microwave metamaterials

Between the design and final realization of a working metasurface lies the potential for a myriad of complications: fabrication tolerances, material permittivity uncertainties, alignment issues and localized defects to name just a few. Global methods of characterizing an entire surface are often incapable of separating these candidates and typically one must resort to the simulation of a wide parameter space to begin to understand experimental discrepancies. In this work we introduce a new imaging technique that is able to locate and discern the resonant frequencies of individual antennas in a complex microwave metasurface. This is achieved with a microwave single-pixel camera using patterned optical excitation of a silicon layer adjacent to the metamaterial to achieve super-resolution. This approach allows us to locate and diagnose fabrication defects, spectrally characterize individual meta-atoms, and visualize inhomogeneous broadening across our samples with below λ/20 resolution, over large areas and in near real-time.