Random lasing films from multifunctional charged optical silica particles

Multifunctional SiO2 particles with charged and fluorescent properties were synthesized and their films with different thickness were prepared using electrophoretic deposition for random lasing. In case of 50-μm-thick film, when the excitation energy density increases above 25 μJ/cm2, spectral narrowing and nonlinear increasing of intensity were observed. To get more information on lasing, single-shot spectrum was measured. Finally, the dependence of the lasing behavior, including the recognition of the existence of a threshold on the film thickness was demonstrated.