Figure 2

Wavelength, thermal, polarization and size dependencies of scattering switching.

(a) By collinearly illuminating a 561-nm laser and a supercontinuum laser onto the sample, scattering spectra with different 561-nm intensities are obtained. In the measurement, a notch filter for 561-nm is inserted, so there is no data points around that spectral region. (b) By heating up the nanoparticles, scattering from a single particle drops significantly, revealing the underlying mechanism is thermally induced change of dielectric constant. (c) Almost identical scattering spectra are obtained when the 561-nm laser polarization is either perpendicular or parallel to the supercontinuum polarization, manifesting that the switching effect is polarization independent with the nanosphere. (d) The nonlinear index distribution with different particle sizes and excitation wavelengths.