Lasing characteristics of random cylindrical microcavity lasers

Abstract

Room-temperature lasing characteristics of random cylindrical microcavity lasers, which can be realized by coating a layer of random gain medium onto the surface of an optical fiber with various diameters, was studied experimentally. It is shown that closed-loop random modes excited inside the random gain medium are strongly confined along the radial direction so that the spacing of lasing modes is controlled by the diameter of cylindrical microcavity. In addition, lasing threshold of the random gain medium can be reduced by an order of magnitude under the influence of radial optical confinement.

Low-threshold lasing action in an asymmetric double ZnO/ZnMgO quantum well structure

“…Consider no artificial optical oscillator cavity and the lasing behavior as observed in the ZnO film, the mechanism of lasing action can be explained by the coherent random lasing 13,14 and the lasing threshold is also close to the previously reported values. 15,16 Lasing actions of the ZnO/ZnMgO MQW and ADQW structures were also studied at room temperature. As shown in Figures 3(b) and 3(c), serious sharp lasing emissions with widths <0.1 nm at around 393 nm and 385 nm, respectively, for the MQW and ADQW samples are clearly observed.…”