Dynamic Optical Lattices Through Conducting Polymer-Gated Confinement

Organic metasurfaces based on conducting polymers are emerging as new opportunities for active nano-optic devices, but their tunable plasmonic resonances are limited to infrared wavelengths (≥960 nm) and mainly with low quality-factors (Q < 2). Here we propose the concept of a "conducting polymer gate" to endow organic metasurfaces with switchable high-Q nonlocal resonances within the visible/NIR-I regime (640-950 nm). Poly(3,4-ethylenedioxythiophene) (PEDOT) is integrated into organic dielectric nanocylinder lattices and serves as a gate that controls optical leakage from the nanocylinders to the substrate. The quasi-metallic PEDOT blocks such leakage channel and induces light confinement within the dielectric nanocylinders despite their low refractive index (n_die < 1.7). This facilitates the generation of Mie collective lattice resonances (CLRs) at the air superstrate with Q-factor reaching 25, which is ∼16 times higher than previously reported organic metasurfaces near this spectral regime. Converting the PEDOT into its dielectric state opens the leakage channel and eliminates the CLRs, which can be reversibly switched by redox reactions. The concept of conducting polymer-gated optical confinement in low-index nanostructures provides new routes for intelligent nano-optics including dynamic nonlocal metasurfaces.