We have investigated complex optical networks containing one or more gain sections, and we have reported the evidence of lasing action; the emission spectrum reflects the topological disorder induced by the connections. A theoretical description compares well with the measurements, mapping the networks to directed graphs and showing the analogies with the problem of quantum chaos on graphs. We have shown that the interplay of chaotic diffusion and amplification leads to an emission statistic with characteristic heavy tails: for different topologies, we have provided an unprecedented experimental demonstration of Lévy statistics, expected for random lasers, for a continuous–wave pumped system.
Contact person: Stefano Lepri, ISC-CNR Sesto Fiorentino