Optical and electrical Kerr effects in polydiacetylene nanoparticle submonolayer probed by surface plasmon resonance spectroscopy

Optical and electrical Kerr effects in a polydiacetylene (PDA) nanoparticle (NP) submonolayer film formed on a gold substrate were investigated. The third-order nonlinear susceptibilities of the PDA NPs at an off-resonance wavelength of 1064 nm were χ(3) = (-7.6 + 6.6i) × 10-9 esu (optical Kerr effect) and χ(3) = (-1.2 + 0.39i) × 10-9 esu (electrical Kerr effect), which are an order of magnitude larger than the value reported. We observed a reflectivity change of 5% with an illumination intensity of 9.3 MW cm-2 in the attenuated total reflection geometry, as a result of the refractive index change of 0.001 on the basis of the optical Kerr effect. The results indicate that the PDA NPs are promising materials for optical switching using plasmonic waveguides. (paper)