A laser is not necessarily a sophisticated device: pumping an amplifying medium randomly filled with scatterers makes a perfectly viable â ̃ random laserâ ™. The absence of mirrors greatly simplifies laser design, but control over the emission wavelength and directionality is lost, seriously hindering prospects for this otherwise simple laser. Recently, we proposed an approach to tame random lasers, inspired by coherent light control in complex media. Here, we implement this method in an optofluidic random laser where modes are spatially extended and overlap, making individual mode selection impossible, a priori. We show experimentally that control over laser emission can be regained even in this extreme case. By actively shaping the optical pump within the random laser, single-mode operation at any selected wavelength is achieved with spectral selectivity down to 0.06 nm and more than 10 dB side-lobe rejection. This method paves the way towards versatile tunable and controlled random lasers as well as the taming of other laser sources.
|Number of pages||6|
|State||Published - Jun 2014|
Bibliographical noteFunding Information:
We thank J. P. Huignard, S. Bhaktha and J. Andreasen for useful discussions. We thank Y. Izmaylov-Mavrikova for her help in the sample microfabrication. P.S., N.B. and S.G. are grateful to the LABEX WIFI (Laboratory of Excellence within the French Program ‘Investments for the Future’) under reference ANR-10-IDEX-0001-02 PSL*. P.S. is grateful to the ANR under Grant No. ANR-08-BLAN-0302-01 and to the Groupement de Recherche 3219 MesoImage. S.G. is funded by the European Research Council (grant number 278025).