Imaging Strongly Coupled Plasmon–Phonon Modes in Mid-Infrared Double Antennas

Strong-coupling effects alter the polaritonic states of metal–dielectric nanostructures and, therefore, can be used to tailor the response of infrared (IR) photonic elements. We report on the development of a simple IR double-nanoantenna platform that achieves strong coupling between plasmon and phonon polaritons using extreme aspect ratio Al and amorphous SiO2 antennas of modest quality-factor, equaling coupling performance of platforms using …