Sign Identification of Nonlinear Refractive Index of Colloidal Nanoparticles by Moiré Deflectometry TechniqueA. Granmayeh Rad, K. Madanipour, A. Koohian and N. TaheriJ. Eur. Opt. Soc.-Rapid Publ., 7 (2012) 12034DOI: https://doi.org/10.2971/jeos.2012.12034