Jeannin, Mathieu Mariotti Nesurini, Giacomo Suffit, Stéphan Gacemi, Djamal Vasanelli, Angela Li, Lianhe Davies, Alexander Giles Linfield, Edmund Sirtori, Carlo Todorov, Yanko Ultrastrong Light–Matter Coupling in Deeply Subwavelength THz LC Resonators The ultrastrong light–matter coupling regime has been demonstrated in a novel three-dimensional inductor–capacitor (LC) circuit resonator, embedding a semiconductor two-dimensional electron gas in the capacitive part. The fundamental resonance of the LC circuit interacts with the intersubband plasmon excitation of the electron gas at ω<sub>c</sub> = 3.3 THz with a normalized coupling strength 2Ω<sub>R</sub>/ω<sub>c</sub> = 0.27. Light–matter interaction is driven by the quasi-static electric field in the capacitors and takes place in a highly subwavelength effective volume <i>V</i><sub>eff</sub> = 10<sup>–6</sup>λ<sub>0</sub><sup>3</sup>. This enables the observation of the ultrastrong light–matter coupling with 2.4 × 10<sup>3</sup> electrons only. Notably, our fabrication protocol can be applied to the integration of a semiconductor region into arbitrary nanoengineered three-dimensional meta-atoms. This circuit architecture can be considered the building block of metamaterials for ultralow dark current detectors. volume V eff;semiconductor;Subwavelength THz LC Resonators;intersubband plasmon excitation;2Ω;electron gas;ultrastrong;circuit 2019-04-02
    https://acs.figshare.com/articles/journal_contribution/Ultrastrong_Light_Matter_Coupling_in_Deeply_Subwavelength_THz_LC_Resonators/7988654
10.1021/acsphotonics.8b01778.s001