Few-Electron Ultrastrong Light-Matter Coupling at 300 GHz with Nanogap Hybrid LC Microcavities

Nano Lett. 2017 Dec 13;17(12):7410-7415. doi: 10.1021/acs.nanolett.7b03228. Epub 2017 Nov 30.


Ultrastrong light-matter coupling allows the exploration of new states of matter through the interaction of strong vacuum fields with huge electronic dipoles. By using hybrid dipole antenna-split ring resonator-based cavities with extremely small effective mode volumes Veff03 ≃ 6 × 10-10 and surfaces Seff02 ≃ 3.5 × 10-7, we probe the ultrastrong light-matter coupling at 300 GHz to less than 100 electrons located in the last occupied Landau level of a high mobility two-dimensional electron gas, measuring a normalized coupling ratio of ΩRc = 0.36. Effects of the extremely reduced cavity dimensions are observed as the light-matter coupled system is better described by an effective mass heavier than the uncoupled one. These results open the way to ultrastrong coupling at the single-electron level in two-dimensional electron systems.

Keywords: Landau levels; THz; Ultrastrong coupling; few electrons; hybrid LC resonator; two-dimensional electron gas.

Publication types

  • Research Support, Non-U.S. Gov't