Electronic and thermal nonlinear refractive indices of SOI and nano-patterned SOI measured by Z-scan method

We measure electronic and thermal nonlinear refractive indices of periodically nano-patterned and un-patterned siliconon-insulator (SOI) in comparison with that of bulk silicon, using a fast reflection Z-scan setup with a high-repetition-rate fs laser (at 800 nm wavelength), and a new procedure for discrimination between electronic and thermal nonlinearities. The electronic nonlinear response of nano-structured SOI is strongly enhanced in comparison with those of un-patterned SOI and of bulk Si. These results could be important in silicon photonics for optical devices with nonlinearity controlled by periodic nano-structuring.