Abstract
Effect of heat treatment on nonlinear optical and optical limiting features of borate based glasses has been ascertained by the Z‒scan technique and the results are discussed in detail. The electron microscopic measurements confirmed the existence of spherical shaped Ag nanoparticles and their growth with heat treatment. The values of the two photon absorption coefficient (α2), nonlinear refractive index (n2) and third‒order nonlinear susceptibility (χ(3)) showed an increase trend with the increase of the heat treatment duration up to 50 h. Subsequently, the nonlinear optical magnitudes decreased at higher heat treatment durations (for 72 h). The enhancement in the nonlinear optical results of the glasses was attributed to the local field stimulated by silver nanoparticles in the vicinity of the Eu3+ ions in the glass matrices. The optical limiting threshold values demonstrated an opposite trend to that of α2. The enhancement in α2 from 2.84 × 10−11 to 4.66 × 10−11 mW−1 and decrement in optical limiting threshold values from 2.85 × 108 to 1.73 × 108 Jcm−2 with variation of heat treatment durations from 0 to 50 h suggest the SNBEuAg0.8‒50 glass is beneficial for designing the photonic limiters to work in the visible region to suppress the high energy laser radiations.
•Efficacy of annealing durations on NLO and OL features of glasses routed with silver NPs has been investigated.•NLO and OL attributes were studied using nanosecond laser pulses by the Z‒scan technique.•The α2, n2 and χ(3) magnitudes were increased with the heat treatment duration up to 50 h.•The OL threshold value demonstrated an opposite trend to that of α2.•The results suggest the SNBEuAg0.8‒50 glass is beneficial for photonic limiters.