Ultrastrong Coupling in the Near-field of Complementary Split Ring Resonators

Understand

The ultrastrong light-matter interaction regime was investigated in metallic and superconducting complementary split ring resonators coupled to the cyclotron transition of two dimensional electron gases.

• The sub-wavelength light confinement and the large optical dipole moment of the cyclotron transition yield record high normalized coupling rates of up to $\frac{\Omega_R}{\omega_c}=$ 0.87.
• We observed a blue-shift of both polaritons due to the diamagnetic term of the interaction Hamiltonian.