Electroluminescent devices based on intersubband polaritons

Full text: The strong coupling between an intersubband excitation and a microcavity photon mode gives rise to mixed light-matter states, the intersubband polaritons. In this presentation, I will report recent results obtained on polaritonic electroluminescent devices in the mid-infrared wavelength range. In an InAs/ AlSb device, we have observed the experimental evidence of polariton and optical phonon scattering. The value of the polariton occupation that we have estimated is very promising for the observation of stimulated scattering in optimized microcavities. The achievement of the ultra-strong coupling regime in mid-infrared metal-dielectric-metal microcavities will also be reported. The experimental signature of this regime is the opening of a photonic gap in the polariton dispersion. These cavities could be employed for realizing active devices in which, thanks to the large value of the Rabi splitting, a selective electrical injection into the polariton states could be achieved, without populating the dark states. (author)