Random lasers driven by engineered pumping

Random lasers (RL) have attracted much attention from the research community but they have been largely regarded as an academic topic with little or no technological interest. Mostly this is due to the fact that, being a system based on disorder, they are hard to subject to any form of control on their performance. Their spectrum is defined by the scattering material which comprises innumerable modes of random shapes and energies filling the gain band of the lasing material. Early advances in trying to gain control over RLs include the tuning of the broad band emission achieved by engineering the scatterers [1]. This permits to channel the gain to a preselected nanometre-broad line and is observed to work in the intensity feedback regime where no single modes are apparent. © 2013 IEEE.