Fig. 1. (a) Schematic of the proposed random laser; (b) TEM images of spherical silver nanoparticles scale bars is 50 nm; (c) TEM images of multi-shaped silver nanoparticles, scale bars is 200 nm. Inset: TEM images of multi-shaped silver nanoparticles, scale bars is 100 nm; (d) Absorption spectrum of spherical silver nanoparticles (yellow) andmulti-shaped silver nanoparticles (blue), photoluminescence spectrum of R6G (orange) and DCJTB (red) membrane

Fig. 2. (a) Emission spectra of PVP-R6G film embedded spherical silver nanoparticles with different pump energy densities; (b) Emission spectra of PVP-R6G film embedded multi-shaped silver nanoparticles with different pump energy densities; (c) Evolution of lasing intensity as functions of pump intensity. The electric-field distribution of the (d) spherical AgNPs, (e) triangle AgNPs, (f) hexagon AgNPs

Fig. 3. (a) Random lasing spectra of the laser at different pump positions; (b) Calculation results of the power Fourier transforms of the random lasing emission spectra

Fig. 4. (a) Emission spectra of the random laser with different pump energy densities; (b) Evolution of lasing intensity as functions of pump intensity