Gold nanoparticles enhanced femtosecond nonlinear optical properties of sodium borate oxide glasses

We present results from our experimental measurements on the effect of annealing and intensity-dependent femtosecond (MHz) third-order nonlinear optical (NLO) attributes of gold nanoparticles (NPs) embedded sodium borate glass specimens. A melt-quench procedure was used to fabricate the gold nanoparticle-loaded sodium antimony containing borate glasses, which were then subjected to different schedules of thermal treatment at 500 degrees C. The highest saturation intensity and nonlinear refraction magnitude were observed for the 7-hour annealed glass specimen (i.e., for NBAu-7 glass). Thus, on the NBAu-7 glass, intensity-sensitive NLO measurements were performed. The saturable absorption behavior that was detected at lower peak intensities switched to reverse saturable absorption during the exposure of NBAu-7 glass with high fluence laser pulses. While the sign of the nonlinear refraction remained unchanged, the magnitude increased. The methodology examined in this work may enable the fabrication of borate-based glasses loaded with gold NPs with high saturation intensities and robust nonlinear refractive index magnitudes to be used in optical switching operations. The results of the current study support that the NBAu-7 glass is advantageous for optical switching functions when exposed to low-energy laser pulses. In contrast, the same glass benefits optical limiting functions when exposed to high-fluence laser pulses.

Automated summary

We conducted experimental measurements on the effect of annealing and intensity-dependent femtosecond third-order nonlinear optical attributes of gold nanoparticles embedded sodium borate glass specimens. The highest saturation intensity and nonlinear refraction magnitude were observed for the 7-hour annealed glass specimen. Nonlinear optical measurements were performed on the NBAu-7 glass, showing a switch from saturable absorption behavior to reverse saturable absorption at high fluence laser pulses.