Low-threshold random lasers based on the DCM-DEG gain system with graphene nanosheets

In this article, low-threshold random lasers based on DCM-DEG (DD) gain system with graphene nanosheets are studied. The experiment results show that the threshold of random lasers reduces rapidly when an appropriate amount of graphene nanosheets is added in DD solution. Meanwhile, the quantity and quality of random lasing modes raise significantly. We discussed the potential reasons why the graphene nanosheets can strengthen the sample's random lasing. And, the influence of the graphene nanosheet concentration on the radiation characteristics of random lasers is further studied. When the concentration of graphene nanosheets is 0.088wt%, the lasing threshold of DD samples with graphene nanosheets (GDD) is only about 31.8% of the lasing threshold of DD samples, and the quality of random lasing modes is five times higher than that of the DD sample. To further reduce the lasing threshold, the gold (Au) nanoparticles are added in the mixed solution to form the GDD solution with Au nanoparticles (GGDD). The results show that the lasing threshold of the GGDD sample is about 7.73 µJ/pulse, which is 5.2% of the lasing threshold of the DD sample. This experiment provides a new method to study low-threshold and high-quality random lasers based on graphene.