Annealing duration dependent optical, nonlinear optical, and optical limiting properties of rare-earth doped glasses embedded with gold nanoparticles

Abstract

In this work, the Eu2O3 doped B2O3 glass specimen embedded with gold nanoparticles (NPs) was designed by the process of melt-quenching and subjected for thermal treatment to understanding the efficacy of thermal dependency on the optical and nonlinear optical (NLO) characteristics. Linear optical studies have revealed a decrease trend in the energy band gap as the function of annealing duration, indicating the increase of non-bridging oxygen concentration in the glass host. The NLO properties were assessed in near-infrared region utilizing 150 fs laser pulses delivered at the rate of 80 MHz. The aperture free Z-scan measurements exhibited an increased nonlinear absorption coefficient with annealing duration. Further, the closed aperture Z-scan data depicted an increase trend in the positive nonlinear refraction with annealing duration and eventually reduced at the greater duration of annealing. The optical limiting studies demonstrated similar behaviour to the nonlinear absorption characteristics of studied glass samples. These results are related to the local field stimulated by surface plasmons of gold NPs near the Eu3+ ions during the exposure of glass to high fluence laser beam. Our results indicate that B2O3 glasses embedded with Au NPs heat-treated for 30 h at 450 °C are good candidates for nonlinear photonic, optoelectronic, and optical power limiting applications in photonics.