Ultrastrong coupling of the cyclotron transition of a two-dimensional electron gas to a THz metamaterial

Understand

Artificial cavity photon resonators with ultrastrong light-matter interactions are attracting interest both in semiconductor and superconducting systems, due to the possibility of manipulating the cavity quantum electrodynamic ground state with controllable physical properties.

• We report here experiments showing ultrastrong light-matter coupling in a terahertz metamaterial where the cyclotron transition of a high mobility two-dimensional electron gas is coupled to the photonic modes of an array of electronic split-ring resonators.
• We observe a normalized coupling ratio $\frac{\Omega}{\omega_c}=0.58$ between the vacuum Rabi frequency $\Omega$ and the cyclotron frequency $\omega_c$.
• Our system appears to be scalable in frequency and could be brought to the microwave spectral range with the potential of strongly controlling the magnetotransport properties of a high-mobility 2DEG.