Enhanced 1.53 µm emission of Er3+ in nano-Ag embedded sodium-boro-lanthanate glasses

The manuscript reports the influence of Ag NPs on the luminescence performance of Er3+ ions activated in borate glass host. The formation and dispersion of Ag NPs in the glass matrices revealed by absorption and HR-TEM measurements. The average size of Ag NPs was found to be 2.80, 7.36, and 16.02 nm, for ELB-1, ELB-2, and ELB-3 glasses, respectively. Utilizing the UV-Visible-NIR absorption spectra, the Judd-Ofelt parameters (Ωλ= 2, 4, 6) were calculated. It was found that the Ω2 values of glasses increased with increase in Ag NPs concentration, suggested that the enhanced covalency and reduced symmetry around the Er3+ ions. The visible luminescence emission under 378 nm excitation shows the emission bands positioned at 535 (2H11/2→4I15/2, green), 547 (4S3/2→4I15/2, green), and 624 (4F9/2→4I15/2, red) nm. NIR emission of all the glasses exhibits an intense peak at 1.53 µm due to 4I13/2 → 4I15/2 transition of Er3+ ions. The visible and NIR emission enhancement was noticed up to 0.1 mol% of AgCl and subsequent quenching at higher concentrations. The mechanisms responsible for luminescence enhancement and quenching has been underlined. The glass host doped with 0.1 mol% of AgCl (i.e., ELB-1) possesses high stimulated emission cross section along with optical gain width which suggests the glass containing 0.1 mol% AgCl is beneficial for solid state IR lasers and fiber-optic communication applications.