Shaping Light Emission by Plasmon Antenna Array Lattice Resonances with Engineered Gain and Loss

Lattice resonances are photonic modes resulting from multiple scattering of light in so-called metasurfaces – dense two-dimensional arrays of polarizable nano-objects. During the past decade, these resonances have been shown to be useful for controlling both spontaneous and stimulated emission of light: especially plasmon nano-antenna arrays have offered improvements in surface-emitting LEDs and lasers in terms of brightness, directivity, and emission efficiency. In our contribution, we will focus on new possibilities that arise when spatially engineering the gain distribution, as opposed to the scatterer geometry. We will present a self-consistent multiple scattering model for metasurfaces with spatially patterned gain. Spatially controlling the gain allows to engineer photonic bands and potentially gives functionalities far beyond simple light amplification. We will in particular focus on structures around points of PT symmetry, and discuss band structures and scattering observables.