Spectral Mueller matrix measurements for characterization of depolarization from non-spherical gold nanoparticles

In this paper we present the results of Mueller matrix measurements on depolarization characteristics of non-spherical gold nanoparticles (rods, tetra-pods, flowers and stars). The measurements show that for all the particle shapes investigated, the depolarization for circularly polarized light is larger than that for linearly polarized light by about a factor of two. Further, depolarization is largest for the rod shaped particles. The wavelength dependence of the depolarization characteristics of the particles was also investigated and the results are consistent with the calculated wavelength dependence of retardance and diattenuation properties of these nanoparticles using discrete dipole approximation.