Effect of silver nanoparticles on fluorescence and nonlinear properties of naturally occurring betacyanin dye

• Betacyanin dye is extracted from red beet root and characterized .
• Silver nanoparticles synthesized by a chemical method and characterized by XRD, HRTEM.
• We show how appropriate concentrations of silver nanoparticles can enable tuning of dye fluorescence efficiency.
• Also shown in the present work how optical limiting threshold can be tuned with varying silver nanoparticle concentrations.
• High nonlinearity we also demonstrated in PVA/Ag nano/Betacyanin composite films.

We present the linear and nonlinear optical studies of a natural dye betacyanin extracted from red beet root in the presence of silver nano particles in colloidal solution. We synthesized silver nano particles and characterized by XRD and HRTEM. We show how appropriate concentration of silver nanoparticles can enable tuning of dye fluorescence efficiency. Nonlinear properties are studied using open aperture Z scan technique with Nd:YAG laser (532 nm, 7 ns, 10 Hz). We show modification of nonlinear properties for the dye to the desired level can be achieved in the presence of silver nanoparticles. High nonlinearity we also demonstrated in PVA/Ag nano/Betacyanin composite films. Theoretical analysis is performed using model based on nonlinear absorption of materials and scattering of metal nanoparticles.