Ultra-strong light-matter coupling in quantum infrared detectors

ongoing

In the majority of optoelectronic devices emission and absorption of light are considered as perturbative phenomena. The objective of my project is to explore the ultra-strong light-matter coupling regime in a new type of optoelectronic semiconductor-based devices operating in the THz and MIR frequency range (lambda=3-300µm). These devices will allow the first time experimental observation of intrinsically quantum features of the ultra-strong coupling regime, such as quantum vacuum radiation (dynamical Casimir effect) and squeezing of polaritons states. In these devices, generically acting as detectors, the light-matter coupled states (polaritons) will be efficiently converted into electrical signals. The matter excitation is based on the electronic transitions in semiconductor quantum wells, where the light-matter interaction is strongly enhanced owe to collective effects. To achieve the ultra-strong coupling regime, the collective electronic excitation is coupled with metamaterial nano-resonator acting as high frequency inductor-capacitive circuit. In such resonator, very high electric field intensity is achieved into effective volume of sizes comparable with the electron De Broglie wavelength. The photoconductivity of such detectors will be dominated by polariton–assisted fermionic transport. The metamaterial detectors will be supplied with sensitive read-out based on the single-electron transistor concept, which will allow the observation of quantum vacuum radiation as well as the non-classical photo-counting statistics of polaritons. In these device architectures I will also implement the dynamical Coulomb blockade, where the single electron charging energy e²/2C becomes comparable with the metamaterial resonator energy ћw. This effect will be exploited as a disruptive approach to sense the quantum-optical properties of light-matter coupled states by all-electronic means.