Blue-light-emitting ZnSe random laser

We observed blue-light-emitting random laser action with coherent feedback in ZnSe particles. Below the threshold excitation, we observed a broad spontaneous emission band peaking at approximately 470 nm. Above the threshold, several discrete lasing lines appear at the center of the spontaneous emission band (approximately 475 nm). The linewidth of each lasing emission is less than 0.4 nm, which is about 40 times narrower than that of the spontaneous emission band. Although the lasing intensity of each line varies from pulse to pulse, the peak wavelengths do not shift significantly. The lasing emission was also found to radiate in all directions.