Modes of random lasers J. Andreasen,1 A. A. Asatryan,2 L. C. Botten,2 M. A. Byrne,2 H. Cao,1 L. Ge,1 L. Labonté,3 P. Sebbah,3,* A. D. Stone,1 H. E. Türeci,4,5 and C. Vanneste3 1Department of Applied Physics, P.O. Box 208284, Yale University, New Haven, Connecticut 06520-8284, USA 2Department of Mathematical Sciences and Center for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), University of Technology, Sydney, New South Wales 2007, Australia 3Laboratoire de Physique de la Matière Condensée, CNRS UMR 6622, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 02, France 4Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland 5Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA *Corresponding author:
[email protected] Received January 21, 2010; revised August 4, 2010; accepted August 6, 2010; published October 1, 2010 (Doc. ID 123020) In conventional lasers, the optical cavity that confines the photons also deter- mines essential characteristics of the lasing modes such as wavelength, emis- sion pattern, directivity, and polarization. In random lasers, which do not have mirrors or a well-defined cavity, light is confined within the gain medium by means of multiple scattering. The sharp peaks in the emission spectra of semi- conductor powders, first observed in 1999, has therefore lead to an intense de- bate about the nature of the lasing modes in these so-called lasers with resonant feedback. We review numerical and theoretical studies aimed at clarifying the nature of the lasing modes in disordered scattering systems with gain.