Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The mode-locking transition of random lasers


The discovery of the spontaneous mode-locking of lasers1,2, that is, the self-starting synchronous oscillation of electromagnetic modes in a cavity, has been a milestone of photonics allowing the realization of oscillators delivering ultrashort pulses. This process is so far known to occur only in standard ordered lasers and only in the presence of a specific device (the saturable absorber). We engineer a mode-selective pumping of a random laser formed by a self-assembled cluster of nanometric particles. We show that the random laser can be continuously driven from a configuration exhibiting weakly interacting electromagnetic resonances4,5 to a regime of collectively oscillating strongly interacting modes6,7. This phenomenon, which opens the way to the development of a new generation of miniaturized and all-optically controlled light sources, may be explained as the first evidence of spontaneous mode-locking in disordered resonators.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: The two random lasing regimes.
Figure 2: From spiky to smooth RL spectra.
Figure 3: Onset of a correlated random laser.
Figure 4: Results from numerical CMT calculations.


  1. Haus, H. Mode-locking of lasers. IEEE J. Sel. Top. Quantum Electron. 6, 1173–1185 (2000).

    Article  ADS  Google Scholar 

  2. Kutz, J. N. Mode-locked soliton lasers. SIAM Rev. 48, 629–678 (2006).

    Article  ADS  MathSciNet  Google Scholar 

  3. Wiersma, D. S. The physics and applications of random lasers. Nature Phys. 4, 359–367 (2008).

    Article  ADS  Google Scholar 

  4. Cao, H. et al. Random laser action in semiconductor powder. Phys. Rev. Lett. 82, 2278–2281 (1999).

    Article  ADS  Google Scholar 

  5. van der Molen, K. L., Tjerkstra, R. W., Mosk, A. P. & Lagendijk, A. Spatial extent of random laser modes. Phys. Rev. Lett. 98, 143901 (2007).

    Article  ADS  Google Scholar 

  6. Letokhov, V. Generation of light by a scattering medium with negative resonance absorption. Zh. Eksp. Teor. Fiz. 53, 1442–1447 (1967).

    Google Scholar 

  7. Lawandy, N. M., Balachandran, R. M., Gomes, A. S. L. & Sauvain, E. Laser action in strongly scattering media. Nature 368, 436–438 (1994).

    Article  ADS  Google Scholar 

  8. Froufe-Pérez, L. S., Guerin, W., Carminati, R. & Kaiser, R. Threshold of a random laser with cold atoms. Phys. Rev. Lett. 102, 173903 (2009).

    Article  ADS  Google Scholar 

  9. Mujumdar, S., Türck, V., Torre, R. & Wiersma, D. S. Chaotic behavior of a random laser with static disorder. Phys. Rev. A 76, 033807 (2007).

    Article  ADS  Google Scholar 

  10. Lepri, S., Cavalieri, S., Oppo, G.-L. & Wiersma, D. S. Statistical regimes of random laser fluctuations. Phys. Rev. A 75, 063820 (2007).

    Article  ADS  Google Scholar 

  11. Leuzzi, L., Conti, C., Folli, V., Angelani, L. & Ruocco, G. Phase diagram and complexity of mode-locked lasers: from order to disorder. Phys. Rev. Lett. 102, 083901 (2009).

    Article  ADS  Google Scholar 

  12. Conti, C., Leonetti, M., Fratalocchi, A., Angelani, L. & Ruocco, G. Condensation in disordered lasers: theory, 3d + 1 simulations, and experiments. Phys. Rev. Lett. 101, 143901 (2008).

    Article  ADS  Google Scholar 

  13. Gouedard, C., Husson, D., Sauteret, C., Auzel, F. & Migus, A. Generation of spatially incoherent short pulses in laser-pumped neodymium stoichiometric crystals and powders. J. Opt. Soc. Am. B 10, 2358–2363 (1993).

    Article  ADS  Google Scholar 

  14. Wiersma, D. S. & Lagendijk, A. Light diffusion with gain and random lasers. Phys. Rev. E 54, 4256–4265 (1996).

    Article  ADS  Google Scholar 

  15. van der Molen, K. L., Mosk, A. P. & Lagendijk, A. Quantitative analysis of several random lasers. Opt. Commun. 278, 110–113 (2007).

    Article  ADS  Google Scholar 

  16. Conti, C. & Fratalocchi, A. Dynamic light diffusion, Anderson localization and lasing in disordered inverted opals: 3d ab-initio Maxwell–Bloch computation. Nature Phys. 4, 794–798 (2008).

    Article  ADS  Google Scholar 

  17. Cao, H. et al. Spatial confinement of laser light in active random media. Phys. Rev. Lett. 84, 5584–5587 (2000).

    Article  ADS  Google Scholar 

  18. Fallert, J. et al. Co-existence of strongly and weakly localized random laser modes. Nature Photon. 3, 279–282 (2009).

    Article  ADS  Google Scholar 

  19. Tureci, H. E., Ge, L., Rotter, S. & Stone, A. D. Strong interactions in multimode random lasers. Science 320, 643–646 (2008).

    Article  ADS  Google Scholar 

  20. Gordon, A. & Fischer, B. Phase transition theory of many-mode ordering and pulse formation in lasers. Phys. Rev. Lett. 89, 103901 (2002).

    Article  ADS  Google Scholar 

  21. Picozzi, A. & Haelterman, M. Condensation in Hamiltonian parametric wave interaction. Phys. Rev. Lett. 92, 103901 (2004).

    Article  ADS  Google Scholar 

  22. El-Dardiry, R. G. S., Mosk, A. P., Muskens, O. L. & Lagendijk, A. Experimental studies on the mode structure of random lasers. Phys. Rev. A 81, 043830 (2010).

    Article  ADS  Google Scholar 

  23. Siddique, M., Alfano, R. R., Berger, G. A., Kempe, M. & Genack, A. Z. Time-resolved studies of stimulated emission from colloidal dye solutions. Opt. Lett. 21, 450–452 (1996).

    Article  ADS  Google Scholar 

  24. Chabanov, A. A., Zhang, Z. Q. & Genack, A. Z. Breakdown of diffusion in dynamics of extended waves in mesoscopic media. Phys. Rev. Lett. 90, 203903 (2003).

    Article  ADS  Google Scholar 

  25. Cao, H., Jiang, X., Ling, Y., Xu, J. Y. & Soukoulis, C. M. Mode repulsion and mode coupling in random lasers. Phys. Rev. B 67, 161101 (2003).

    Article  ADS  Google Scholar 

  26. van der Molen, K. L., Tjerkstra, R. W., Mosk, A. P. & Lagendijk, A. Spatial extent of random laser modes. Phys. Rev. Lett. 98, 143901 (2007).

    Article  ADS  Google Scholar 

Download references


This work was supported by ERC grant FP7/2007-2013 no. 201766; CINECA; EU FP7 NoE Nanophotonics4Enery grant no. 248855; the Spanish MICINN CSD2007-0046 (; MAT2009-07841 (GLUSFA) and Comunidad de Madrid S2009/MAT-1756 (PHAMA).

Author information

Authors and Affiliations



All authors contributed equally to the work presented in this Letter.

Corresponding author

Correspondence to Cefe Lopez.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 2002 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Leonetti, M., Conti, C. & Lopez, C. The mode-locking transition of random lasers. Nature Photon 5, 615–617 (2011).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing