Polariton-polariton scattering: Exact results through a novel approach

¹  Institut des NanoSciences de Paris (INSP), Université Pierre et Marie Curie-Paris 6, Université Denis Diderot-Paris 7, CNRS, UMR 7588 - Campus Boucicaut, 140 rue de Lourmel, 75015 Paris
²  Laboratoire d'Optoélectronique Quantique, Ecole Polytechnique Fédérale de Lausanne (EPFL) Station 3, CH-1015 Lausanne, Switzerland

Received: 13 February 2007
Accepted: 15 May 2007

Abstract

We present a fully microscopic approach to the transition rate of two exciton-photon polaritons. The non-trivial consequences of the polariton composite nature —here treated exactly through a development of our composite-exciton many-body theory— lead to results noticeably different from the ones of the conventional approaches in which polaritons are mapped into elementary bosons. Our work reveals an appealing fundamental scattering which corresponds to a photon-assisted exchange —in the absence of Coulomb process. This scattering being dominant when one of the scattered polaritons has a strong photon character, it should be directly accessible to experiment. In the case of microcavity polaritons, it produces a significant enhancement of the polariton transition rate when compared to the one coming from Coulomb interaction. This paper also contains the crucial tools to securely tackle the many-body physics of polaritons, in particular towards its possible BEC.