Beam quality of a nonideal atom laser

Authors :: M. Fauquembergue
Y. Le Coq
Philippe Bouyer
Alain Aspect
William Guerin
Vincent Josse
J.-F. Riou
laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
Laboratoire Charles Fabry de l'Institut d'Optique (LCFIO)
Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Sud - Paris 11 (UP11)
Source :: Physical Review Letters, Physical Review Letters, American Physical Society, 2006, 96, pp.070404. ⟨10.1103/PhysRevLett.96.070404⟩
Publication Year :: 2005
Abstract: International audience; We study the propagation of a non-interacting atom laser distorted by the strong lensing effect of the Bose-Einstein Condensate (BEC) from which it is outcoupled. We observe a transverse structure containing caustics that vary with the density within the residing BEC. Using WKB approximation, Fresnel-Kirchhoff integral formalism and ABCD matrices, we are able to describe analytically the atom laser propagation. This allows us to characterize the quality of the non-ideal atom laser beam by a generalized M$^2$ factor defined in analogy to photon lasers. Finally we measure this quality factor for different lensing effects.