Far-field imaging with a multi-frequency metalens

Studying a finite size array of closed sub-wavelength resonators, we show that we gain control on the array modes when cell resonances are different. Using such an array made of SRR, we build a multi-frequency metalens. In stead of using the sub-wavelength-varying modes as in classic metalenses, here we exploit mitigated localized modes to perform straightforward sub-wavelength far-field imaging. With this concept, we prove numerically and experimentally that we can image a sub-wavelength pattern from far-field measurements.