Enhanced thermal stability and nonlinear optical response in gold nanoparticles dispersed Na2O–B2O3–SiO2 glass
摘要
In the present study, characterization of sodium borosilicate glass embedded with gold nanoparticles (GNPs) prepared using the melt-quench technique has been explored. The addition of GNPs to the glass matrix is shown to significantly impact its structural, thermal, and optical properties. X-ray diffraction analysis confirms the non-crystalline nature of the glass, even with the presence of GNPs. Field emission scanning electron microscopy reveals 400 nm grains, likely formed by the aggregation of smaller nanoparticles during annealing to overcome the surface stresses. High-resolution transmission electron microscopy further substantiates these findings by unveiling the internal structure of these grains, showing non-uniformly dispersed GNPs with an average size of ~ 2.5 nm. Differential thermal analysis shows the improvement in thermal stability of glass from 178 to 211 °C after the introduction of GNPs making them suitable for fiber-drawing applications. UV-VIS-NIR spectroscopy demonstrates a slight increase in transmission, whereas the optical band gap is reduced from 3.5 eV in the undoped glass to 3.1 eV in the glass containing GNPs, indicating modifications in the energy levels within the glass network. Further, an increase in the refractive index from 2.27 to 2.37, as well as a significant enhancement in third-order nonlinear susceptibility from 2.07 × 10−12 esu to 3.11 × 10−12 esu is observed. The nonlinear refractive index also increased from 3.43 × 10−11 cm2/W to 4.95 × 10−11 cm2/W, demonstrating improved nonlinear optical response due to the presence of GNPs. These enhancements are attributed to increased non-bridging oxygens, resulting in greater hyperpolarizability. The findings highlight the potential of GNP-doped glasses for waveguiding devices.