Amplified spontaneous emission and random laser generation in capillaries doped with rhodamine 6G–microspheres

Amplified spontaneous emission and random lasing were demonstrated in capillaries of different diameters doped with Rhodamine 6G and monodisperse polystyrene microspheres as the gain medium. The emission intensity was enhanced by adding polyvinyl pyrrolidone polymer to the solution. The degree of polarization of the lasing emission can be controlled by the state of pump polarization due to the anisotropic gain of the dye molecule. Lasing spectral widths were simulated with the time-dependent theory for random lasers and generally confirmed the experimentally measured values. Therefore, we present a new, to the best of our knowledge, way to modulate the characteristics of optofluidic random lasers and promote the ability to design random lasers.