Phonon‐Polariton Mediated Dual Electromagnetically Induced Transparency‐Like Response in a THz Metamaterial

Abstract Light and matter can intertwine to create entirely new quantum states in the so‐called strong‐coupling regime, allowing unprecedented control over electromagnetic waves. In this work, strong‐coupling mediated polaritonic states are exploited to demonstrate tunable dual electromagnetically induced transparency (EIT) like response in the terahertz (THz) frequency range using a micron‐sized metamaterial system coupled with the phonon mode of a lead halide perovskite film. This architecture allows to reversibly switch between the single and the dual EIT‐like behavior without modifying the metamaterial structures. The dual EIT‐like nature is further confirmed through the in‐plane electric field distributions and the slow‐light effects. The specific structural symmetry further allowed us to effectively switch between the dual EIT‐like response and the conventional strong‐coupling responses. Such tunability bears potential implications for developing metamaterial‐phonon‐based tunable THz devices such as switches, filters, and slow‐light devices.