Random laser with cold atoms

A random laser is a laser without cavity, in which feedback is provided by multiple scattering in the gain medium. This kind of lasers has been studied for a few years and is still a hot topics in the photonics community.

A cold atom cloud can give rise to multiple scattering and we have shown that it can also provide enough gain to sustain lasing (with a cavity) [1]. However, combining gain and multiple scattering simultaneously is far from being easy. We have investigated this issue by quantifying the random laser threshold for different gain mechanisms [2-4].

We finally found a gain mechanism, based on stimulated Raman scattering between hyperfine ground states, that can provide gain in the vicinity of a scattering resonance. Since atoms are pumped on an open transition, it leads to a complicated interplay between radiation trapping and optical pumping [5]. Nevertheless, a fine tuning of the parameters allowed us to observe evidence of random lasing in cold atoms, which manifests itself by an enhancement of the fluorescence emitted by the cloud [6].

Several questions remain open, like the temporal dynamics of the random laser and its coherence properties. These are the subject of our current work.


People currently involved in this project:

Robin Kaiser, William Guerin, Mathilde Fouché, Aurélien Eloy (PhD, 2015-2018)


People involved in the past:

Samir Vartabi Kashanian (PhD, 2013-2016), Quentin Baudouin (PhD, 2010-2013), Djeylan Aktas (Master, 2013), Nicolas Mercadier (Master & PhD, 2008-2011), Verra Guarrera (Postdoc, 2009-2010), Davide Brivio (Master, 2008), Franck Michaud (PhD, 2005-2008)

External collaborators: Dmitriy Kupriyanov (Saint-Petersburg, Russia), Luis Froufe-Pérez (Madrid, Spain), Rémi Carminati (Paris), Sergey Skipetrov (Grenoble).



This project has started in 2007 with the financial support of the French ANR (Agence National pour la Recherche) through the grant ANR-06-BLAN-0096 (see all publications related to this project). Several PhD students involved in this project have been supported by DGA grants.




  1. Mechanisms for Lasing with Cold Atoms as the Gain Medium
    W. Guerin, F. Michaud, R. Kaiser,
    Phys. Rev. Lett. 101, 093002 (2008), preprint: physics/0804.0109
  2. Threshold of a Random Laser with Cold Atoms
    L. Froufe-Pérez, W. Guerin, R. Carminati and R. Kaiser
    Phys. Rev. Lett. 102, 173903 (2009), preprint: physics/0812.0266
    Press : Physical Review Focus / PhysOrg.Com / Photonics Spectra
  3. Threshold of a random laser based on Raman gain in cold atoms
    W. Guerin, N. Mercadier, D. Brivio and R. Kaiser
    Opt. Express 17, 11236 (2009), preprint: physics/0903.5190
  4. Towards a random laser with cold atoms
    W. Guerin, N. Mercadier, F. Michaud, D. Brivio, L. S. Froufe-Pérez, R. Carminati, V. Eremeev, A. Goetschy, S. E. Skipetrov, R. Kaiser
    J. Opt 12, 024002 (2010), preprint: physics/0906.0714
  5. Steady-state signatures of radiation trapping by cold multilevel atoms
    Q. Baudouin, N. Mercadier, R. Kaiser
    Phys. Rev. A 87, 013412 (2013), preprint: physics/1208.1884
  6. A cold-atom random laser
    Q. Baudouin, N. Mercadier, V. Guarrera, W. Guerin, R. Kaiser
    Nature Phys. 9, 357 (2013), preprint: physics/1301.0522
    See also Lasers: Amplified by randomness, by V. Vuletic, Nature Phys. News and Views 9, 325 (2013).
    Press: Physics World, MIT Technology Review, Wired, POPSCI, Le fil UNS, WebTimeMedias, INP CNRS.
  7. Cold and hot atomic vapors: a testbed for astrophysics?
    Q. Baudouin, W. Guerin, R. Kaiser
    in Annual Review of Cold Atoms and Molecules, vol. 2, edited by K. Madison, K. Bongs, L. D. Carr, A. M. Rey, and H. Zhai
    World Scientific, Singapour, 2014
    Preprint: hal-00968233
  8. Raman process under condition of radiation trapping in a disordered atomic medium
    L.V. Gerasimov, V. M. Ezhova, D. V. Kupriyanov, Q. Baudouin, W. Guerin, R. Kaiser
    Phys. Rev. A 90, 013814 (2014), preprint: arXiv:1401.6641
  9. Diffusive to quasi-ballistic random laser: incoherent and coherent models
    W. Guerin, Y. D. Chong, Q. Baudouin, M. Liertzer, S. Rotter, R. Kaiser
    J. Opt. Soc. Am. B 33, 1888 (2016), preprint: arXiv:1606.03679
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See also the Master and PhD thesis: