Continuously tunable ultrastrong light-matter interaction

摘要

We present results on the continuous tuning of the interaction strength between the cyclotron transition in a two dimensional electron gas (2DEG) and the LC mode of THz split ring resonators (SRRs) with ω_(LC) = 2π × 0.52 THz. The interaction strength is continuously modified in a gated sample by changing the electron density in the 2DEG. We observe an asymmetric emergence of the polaritonic branches at the onset of the ultrastrong coupling. Both, the line widths and transmission amplitudes are modulated when moving from the weak coupling regime to the ultrastrong coupling regime reaching a normalized coupling rate π/ω = 0.21.