Direct polariton-to-electron tunneling in quantum cascade detectors operating in the strong light-matter coupling regime

Abstract

We demonstrate mid-infrared quantum cascade detectors (QCD) operating in the strong light-matter coupling regime. They operate around λ = 10 µm with a minimum Rabi splitting of 9.3 meV. A simple model based on the usual description of transport in QCDs does not reproduce the polaritonic features in the photo-current spectra. On the contrary, a more refined approach, based on the semi-classical coupled modes theory, is capable to reproduce both optical and electrical spectra with excellent agreement. By correlating absorption/photo-response with the simulations, we demonstrate that -in this system -resonant tunneling from the polaritonic states is the main extraction mechanism. The dark intersubband states are not involved in the process, contrary to what happens in electrically injected polaritonic emitters.

High speed, antenna-enhanced 10.3 μ m quantum cascade detector

“…Detailed investigations on the interplay between absorption and photoresponse, in particular, the key role played by intersubband polaritons can be found in a dedicated paper. 31 The voltage dependence of the photocurrent under normal illumination by a 10.3 lm quantum cascade laser [QCL, green line in Fig. 3(a)] is plotted in Fig.…”