Enhanced resonant nonlinear optical traits and optical limiting performance of metal nanoparticles containing borate glasses in nanosecond pulse regime

We have initially optimized the alkali (sodium) oxide concentration in the glass matrix by investigating the nonlinear optical (NLO) characteristics of sodium oxide varied gold nanoparticles (NPs) embedded zinc borate-based glass hosts. It was identified that the third-order NLO features were maximum for 30 mol% sodium oxide containing glasses. For tuning the NLO characteristics, the gold NPs bearing optimized glass host was thermal treated near glass transition temperature for different dwell time. In order to ascertain the NLO features, the Z-scan technique was employed using pulses of nanosecond laser fired at 1 kHz at 532 nm. It was noted that, the nonlinear optical absorption (two-photon), refraction (negative) and third-order nonlinear optical susceptibility magnitudes were improved with increase of alkali content in the composition on account of increased formation of gold NPs. The NLO coefficients were further improved to higher order with annealing duration due to the gold NPs' growth. The outcomes endorse the 30 mol% sodium oxide bearing glass embedded with gold NPs annealed for 12 hrs at 450 degrees C are useful for bio-imaging, harmonic generation and optical limiting applications to work in visible region.

Automated summary

We optimized the concentration of alkali (sodium) oxide in the glass matrix and studied the characteristics of gold nanoparticles embedded in zinc borate-based glass hosts for nonlinear optical properties. We found that glasses containing 30 mol% sodium oxide had the maximum third-order nonlinear optical features. By thermal treating the gold nanoparticles with the optimized glass host at different dwell times near the glass transition temperature, we were able to tune the nonlinear optical characteristics. The results showed that increasing the alkali content in the glass composition led to improved nonlinear optical absorption, refraction, and third-order nonlinear optical susceptibility due to increased formation of gold nanoparticles.