Letter abstract

Nature Physics 4, 924 - 927 (2008)
Published online: 12 October 2008 | doi:10.1038/nphys1096

Subject Categories: Atomic and molecular physics | Optical physics | Quantum physics

Strong interaction between light and a single trapped atom without the need for a cavity

Meng Khoon Tey1, Zilong Chen2, Syed Abdullah Aljunid1, Brenda Chng1, Florian Huber3, Gleb Maslennikov1 & Christian Kurtsiefer1


Many quantum information processing protocols require efficient transfer of quantum information from a flying photon to a stationary quantum system1, 2, 3. To transfer information, a photon must first be absorbed by the quantum system. This can be achieved, with a probability close to unity, by an atom residing in a high-finesse cavity1. However, it is unclear whether a photon can be absorbed effectively by an atom in a free space. Here, we report on an observation of substantial extinction of a light beam by a single 87Rb atom through focusing light to a small spot with a single lens. The measured extinction values can be directly compared to the predictions of existing free-space photon–atom coupling models4, 5, 6. Our result should open a new perspective on processing quantum information carried by light using atoms, in particular for experiments that require strong absorption of single photons by an atom in free space.

  1. Center for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, 117543, Singapore
  2. Institute of Materials Research and Engineering, 3 Research Link, 117602, Singapore
  3. Department of Physics, Technical University of Munich, James Franck Street, 85748 Garching, Germany

Correspondence to: Christian Kurtsiefer1 e-mail: christian.kurtsiefer@gmail.com