Abstract:In this talk, I will discuss about the recent results obtained with an amplifying linear array of micro-droplets, which realizes a 1D periodic-on-average random system (PARS) under some controlled conditions. Transfer matrix calculations with gain demonstrated the origin of single mode lasing under spectral mode-matched condition and threshold dependence of lasing modes with the strength of disorder. By tweaking the size of the micro-resonators, we experimentally implemented a spectral mode-matched system which yielded single mode coherent random lasing with a probability of 76%. The modes were observed to be restricted to a bandwidth of 1.2 nm, thus offering quasi-stability in the emission. In another set of experiments, PARS system realizes the perturbed band-edge and single mode random lasing configurations under the condition of quasi-periodicity. Numerical calculations conclude that a higher threshold is required for triggering the perturbed band edge lasing compared to the random lasing mode in a quasi-periodic system. Statistical analyses of lasing spectra and the intensity differences of lasing peaks of perturbed band-edge and random lasing modes conclusively indicate the experimental realization of a quasi-periodic system.