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Collective effects and super-luminesce in two dimensional systems

Mercredi 20 mars 2013 15:00 - Duree : 1 heure
Lieu : Salle René Pauthenet, J229 - Bât J au 2ème étage, LNCMI - 25 rue des martyrs - 38000 Grenoble

Orateur : Carlo SIRTORI (Université Paris 7)

Light-matter strong interaction can substantially modify the electronic spectrum of semiconductor unipolar devices. In fact, optical excitations in 2 dimensional systems can strongly interact with a microcavity photonic mode and give rise to mixed light-matter states, the polaritons[1,2]. These new states are energetically separated from the original electronic states of the system and can be accessed by injecting electrons into their matter part, thus obtaining efficient emitter and detectors in the far- and mid-infrared wavelength range. To this end we have conceived new device architectures in which active materials are embedded within metal-dielectric micro-cavities with ultra-strong light confinement [3] in the order of Vmcavity/(lvaccum ) 3 = 10-6. To enhance the coupling strength of the light matter interaction, thus separating even further the polaritonic states from those electronic, it is necessary to increase the number of available excitations that interact with the photons of the cavity mode. This is readily obtained by increasing the doping density. For very high electronic densities, when the Fermi level occupies more than one subband, very important collective effects appear [4]. The interaction between dipoles becomes so strong that phases all the transitions of the systems giving rise to important renormalisation and supperradiant effects. A strong electroluminescent signal can be measured from these renormalized states, first evidence of super-coherent emission. References : [1] Y. Todorov and C. Sirtori, Phys. Rev. B 85, 045304 (2012) [2] Y. Todorov, et al., Phys. Rev. Lett. 105, 196402 (2010) [3] C. Feuillet-Palma, et al., Scientific Rep. 3, srep01361 (2013) [4] A. Delteil, et al., Phys. Rev. Lett. 109, 246808 (2012).

Contact : clement.faugeras@lncmi.cnrs.fr

Discipline évènement : (Physique)
Entité organisatrice : (LNCMI)
Nature évènement : (Séminaire)
Site de l'évènement : Polygone scientifique

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