Random laser action in the visible region by dye-based sliver nano-hexagonal colloid media

Abstract

In our attempt to reduce the threshold for dye-based random lasers, a new kind of random lasing media is demonstrated based on silver nano-hexagonal as scattering centers. For this purpose, we use a chemical method to synthesize nano hexagonal silver scatterer points and dissolve them in polymer and Rhodamine B dye media in different concentrations and different sizes. Our results from these samples under different pumping power, confirm the strong dependence on the sizes and concentration on the transition from incoherent to the coherent random laser, which is starts from 0.061 MW cm−2 as threshold power. This threshold power and linewidths of emission peaks decrease by an increase in the size and concentrations of nano-hexagonal points to 0.04 MW cm−2 and 0.2 nm, respectively.