Coupling of nanoantennas in loss-gain environment for application in active tunable metasurfaces

A generic model of two dissimilar antenna-type resonators coupled both via near-field and far-field embedded in active gain and/or loss medium is considered. Conditions required for hitting the superscattering regime corresponding to threshold lasing emission operation are established. It shown that modulation losses level within realistic parameters an efficient approach implementation tunability. This two-antenna setup can serve as inspiration high-contrast tunable metasurfaces.