Two-Dimensional Double-Quantum Spectra Reveal Collective Resonances in an Atomic Vapor

Xingcan Dai, Marten Richter, Hebin Li, Alan D. Bristow, Cyril Falvo, Shaul Mukamel, and Steven T. Cundiff

Phys. Rev. Lett. 108, 193201 – Published 7 May 2012

Abstract

We report the observation of double-quantum coherence signals in a gas of potassium atoms at twice the frequency of the one-quantum coherences. Since a single atom does not have a state at the corresponding energy, this observation must be attributed to a collective resonance involving multiple atoms. These resonances are induced by weak interatomic dipole-dipole interactions, which means that the atoms cannot be treated in isolation, even at a low density of $10^{12} {cm}^{- 3}$ .

Received 11 November 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.193201

Authors & Affiliations

Xingcan Dai^1,*, Marten Richter^2,†, Hebin Li¹, Alan D. Bristow^1,‡, Cyril Falvo^2,§, Shaul Mukamel², and Steven T. Cundiff¹

¹JILA, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309-0440, USA
²Department of Chemistry, University of California, Irvine, California 92697-2025, USA

^*Present address: Department of Physics, Tsinghua University, Beijing 100084 China.
^†Present address: Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
^‡Present address: Department of Physics, West Virginia University, Morgantown, WV 26506-6315, USA.
^§Present address: Institut des Sciences Moléculaires d’Orsay, UMR CNRS 8214, Université Paris Sud 11, 91405 Orsay, France.