Single Metallic Nanoparticle Sensitivity with Hyper Rayleigh Scattering

We report. experiments where single metallic nanoparticle sensitivity is achieved with hyper Rayleigh scattering. To reach this level of sensitivity, long acquisition times and signal statistics were required. In particular, a careful study of the intensity fluctuations with time was undertaken and the first, second and third moments of the intensity distribution were determined. From this analysis, the hyperpolarizability of a silver metallic nanoparticle, the diameter of which is 80 nm, was measured and found to be beta = (206 +/- 20) x 10(-25) esu at 800 nm.