Resonances in Mie scattering by an inhomogeneous atomic cloud

¹ University of Nova Gorica, School of Applied Sciences - Vipavska 11c SI-5270 Ajdovcina, Slovenia, EU
² Instituto de Física de São Carlos, Universidade de São Paulo - 13560-970 São Carlos, SP, Brazil
³ Institut Non Linéaire de Nice, CNRS, Université de Nice Sophia-Antipolis - F-06560 Valbonne, France, EU
⁴ Dipartimento di Fisica, Università Degli Studi di Milano - Via Celoria 16, I-20133 Milano, Italy, EU

^a bachelard.romain@gmail.com

Received: 6 September 2011
Accepted: 17 November 2011

Abstract

Despite the quantum nature of the process, collective scattering by dense cold samples of two-level atoms can be interpreted classically describing the sample as a macroscopic object with a complex refractive index. We demonstrate that resonances in Mie theory can be easily observable in the cooperative scattering by tuning the frequency of the incident laser field or the atomic number. The solution of the scattering problem is obtained for spherical atomic clouds who have the parabolic density characteristic of BECs, and the cooperative radiation pressure force calculated exhibits resonances in the cloud displacement for dense clouds. At odds with uniform clouds which show a complex structure including narrow peaks, these densities show resonances, yet only under the form of quite regular and contrasted oscillations.