The graphene and nanoparticles composites have novel optical and electrical properties. They are widely used in the fields of information sensing, photoelectric conversion and medical diagnosis. Graphene has excellent photoelectric properties and can regulate the random laser properties, but the current composite process of graphene with special structures and metal nanostructures is complicated. Thus, there is still a challenge to effectively reducing the threshold of random laser by using graphene. In this work, the Au/graphene structure is prepared by convenient chemical reduction and adsorption method, and the dye DCJTB is used as the gain medium to form the film by spin coating. The random laser properties of Au nanoparticles and Au/graphene structure are studied, and the mechanism of graphene is analyzed. The results show that the transmission peak of Au/graphene composite is near the photoluminescence peak of gain medium, which promotes the energy level transition of dye molecules. With the addition of graphene into the same gain medium, the scattering frequency of photons in the disordered medium increases, resulting in the enhancement of surface plasmon resonance. The scattering effect and the surface plasmon resonance effect cooperate with each other, showing good random laser threshold, which is reduced from 3.4 μJ/mm² to 2.8 μJ/mm². Repeatability and high quality of maser are obtained by repetitively measuring the same sample, showing that the lasing sample has good repeatability and high quality. This study plays a certain role in promoting the application of random laser and t realizing the high-performance optoelectronic devices.

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As the third-generation semiconductor electronic material, silicon carbide (SiC) has good chemical stability and mechanical properties, leading to wide use in optoelectronic components, fiber sensing and detectors. However, there are few important reports on its application in the research of random laser. Hereby, we built a polymer random laser system with SiC nanowires as a scattering medium doped with dye by the spin coating method. The effect of different SiC concentrations on random laser properties and the enhancement mechanism are studied. The lasing intensity increases and threshold decrease in large concentration SiC nanowires at the same lasing system, and the minimum threshold is 20 μJ/pulse. By increasing the SiC concentration, the mean free path of photon scattering decreases, which promotes the photon gain effect and improves the laser performance. However, when the concentration of SiC nanowires is too large, the mean free path of photon scattering decreases further, and the self-absorption of fluorescence radiation emerges. Thus, fluorescence quenching is produced, leading to a negative effect on laser performance. Furthermore, the lasing wavelength can be adjusted by tuning the SiC nanowires concentrations, reaching 14nm. The random laser enhanced by SiC nanowires is stable and pumped repeatable, which could pave the way to promote the application of SiC and achieve low-cost and high-performance random laser.

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