One axis guided random laser emission from a glass capillary composite

Random lasers are structures in which light is both, multiply scattered and amplified. The present study uses Rhodamine B and organic-inorganic hybrid materials to investigate the random lasing properties of silica capillary systems. The composite was prepared by dispersing the dye into an aluminoxane-epoxy-siloxane hybrid together with Boehmite powder, which are subsequently used to fill fused silica capillaries. In this system, Rhodamine B and Boehmite particles act at the same time as a gain and scattering medium, respectively. Random laser emission was performed by using the second harmonic of a 100-ps Nd:YAG laser as pump source; a typical laser threshold behavior was observed for a pumping fluency of 6 mu J/mm(2). The random laser emission spectrum also displays a tunable behavior. This resulted from a combination of the broad emission spectrum of the dye with the different Boehmite particle sizes allied with the advantage of the capillary geometry. (AU)