Optical limiting and nonlinear optical properties of silver nanoparticles embedded glasses containing rare-earth ions at 532 nm under nanosecond regime.

Efficacy of silver nanoparticles concentration and annealing durations on optical limiting and optical nonlinearities of borate based glasses bearing the composition (79.5–x)B₂O₃–15Na₂O–5La₂O₃–0.5Sm₂O₃–xAgCl (mol%) was assessed by Z-scan approach under the pumping of visible light (532 nm) in nanosecond regime. The dual photon absorption parameter (α₂) was elevated from 0.576 × 10⁻¹¹ to 1.201 × 10⁻¹¹ m/W with AgCl content from 0 to 0.5 mol%. This α₂ further raised to 1.964 × 10⁻¹¹ m/W when the optimized glass host heat treated at 450° C for 25 h. Similarly, the index of nonlinear refraction (n₂) was enhanced from 1.642 × 10⁻¹⁹ to 2.532 × 10⁻¹⁹ m²/W as the AgCl content increased from 0 to 0.5 mol%. This n₂ value in turn monotonously increased to 2.963 × 10⁻¹⁹ m²/W when optimized glass system annealed at 450° C for 25 h. The optical limiting threshold magnitude followed reverse trend compared to α₂ and n₂. The enhancement in nonlinear optical features and optical limiting efficiencies were related to field stimulated by Ag⁰ nanoparticles when excited with high energy radiation. However, the non-uniform local field generated when the glass nanocomposites heated for longer duration resulted the switching of nonlinear absorption. The nonlinear optical and optical limiting results infer the 0.5 mol% AgCl encompassing glass sample annelaed at 450 °C for 25 h is benificail for construction of power optical limiters to operate in the visible range. [ABSTRACT FROM AUTHOR]