Optoelectronic switching in a microstructure containing Au nanoparticles

Photoconduction and nonlinear optical refraction effects exhibited by an array of separated Au microchannels are reported. The samples were constituted by Au thin solid films containing Au nanoparticles prepared by an evaporation method. The photoconductivity of the sample was measured with continuous illumination at 532 nm wavelength with 1 W average power. A vectorial two-wave interaction allowed us to explore the optical Kerr effect exhibited at 532 nm wavelength and 1 ns pulse duration. Z-scan experiments performed in a comparative Au thin solid film pointed out a saturated optical absorption as a dominant physical mechanism that originates the optical nonlinearity at 1064 nm wavelength with 150 ps pulses. The third-order optical nonlinearities measured in the studied cases with ps and ns pulses were estimated to be about |X⁽³⁾₁₁₁₁| = 10^-10 esu. Microscopy observations were carried out to describe the morphology that is responsible for the noticeable optical Kerr effect. The optoelectronic switching behavior exhibited by the studied array was analyzed.