Demonstration of ultra-small MIR acoustic-graphene-plasmon cavities based on magnetic resonators

Acoustic-graphene-plasmons (AGPs) are highly confined electromagnetic modes, which carry extreme momentum and low loss in the Mid-infrared (MIR) to Terahertz (THz) spectra. In this work [1], we demonstrate a new way to excite AGPs from the far-field, which are confined to nanometric-scale cavities, via localized graphene-plasmon-magnetic-resonators (GPMRs). This approach enables the efficient excitation of single AGP cavities, which are able to confine MIR light to record-breaking ultra-small mode-volumes that are ∼5·1010 times smaller than their free-space volume.