High non-resonant third-order optical nonlinearity of Ag–glass nanocomposite fabricated by two-step ion exchange

• Published in: Optical materials 2013-12, Vol.36 (2), p.328-332
• Main Authors: Karvonen, L., Rönn, J., Kujala, S., Chen, Y., Säynätjoki, A., Tervonen, A., Svirko, Y., Honkanen, S.
• Format: Article
• Language: English
• Subjects: Doped-insulator lasers and other solid state lasers; Exact sciences and technology; Femtosecond; Fundamental areas of phenomenology (including applications); Lasers; Nanoparticles; Nanostructure; Nonlinearity; Optics; Physics; Refractive index; Refractivity; Saturable absorption; Silver; Silver nanoparticle; Third-order nonlinearity; Z-scan
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2013.09.016

•Ag nanoparticles were fabricated by two-step ion exchange into glass.•Third-order nonlinearities were studied using Z-scan technique.•A femtosecond laser at 800nm wavelength was used as excitation source.•The high nonlinear refractive index n2 at the level of 10−10cm2/W was obtained.•The measured nonlinear absorption coefficient β of −1.9×10−5cm/W was extremely high. We observe high third-order optical nonlinearity of Ag–glass nanocomposite fabricated by a two-step ion exchange method. The nonlinear refractive index and absorption are studied using the well-known Z-scan technique. In our experiments, we use a femtosecond Ti–Sapphire laser source operating at 800nm, which is far from the plasmon resonance of the Ag nanoparticles. Our nanoparticles possess a high positive nonlinear refractive index and also a very high saturable absorption. We estimate the nonlinear refractive index to be on the order of 10−10cm2/W and the saturable absorption to be on the order of 10−5cm/W.