Active subnanometer spectral control of a random laser

We demonstrate an experimental technique that allows to achieve a robust control on the emission spectrum of a micro random laser and to select individual modes with sub-nanometer resolution. The presented approach relies on an optimization protocol of the spatial profile of the pump beam. Here we demonstrate not only the possibility to increase the emission at a wavelength but also that we can isolate an individual peak suppressing unwanted contributions form other modes. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792759]