Third-order nonlinear optical vitreous material derived from mesoporous silica incorporated with Au nanoparticles

Abstract

Mesoporous silica SBA-15 encapsulated with Au nanoparticles was consolidated by spark plasma sintering. It turned out to be an original and facile preparation route for incorporating Au nanoparticles in silica glass. The incorporation of Au nanoparticles in a silica glass matrix made the obtained glass coloured dark wine-red due to the surface plasmon resonance effect of Au nanoparticles, although the concentration of Au nanoparticles was extremely low (about 0.05 wt%). Besides, the Z-scan method using a femtosecond laser pulse was employed to measure the nonlinear optical property of this mesoporous composite-derived glass, which exhibited self-focusing feature at 720 nm with saturable absorption. The third-order nonlinear refraction index n₂ and absorption coefficient β were 1.74 × 10⁻¹⁸ m² W⁻¹ and −5.72 × 10⁻¹² m W⁻¹, respectively. We believe that this approach could be extended to disperse other metal or semiconductor nanoparticles in a glass matrix.