Four widely used electromagnetic field solvers are applied to the problem of scattering by a spherical or spheroidal silver nanoparticle in glass. The solvers are tested in a frequency range where the imaginary part of the scatterer refractive index is relatively large. The scattering efficiencies and near-field results obtained by the different methods are compared to each other, as well as to recent experiments on laser-induced shape transformation of silver nanoparticles in glass.

By irradiating spherical metal nanoparticles embedded in glass with several hundred ultrashort laser pulses at peak intensities of 0.2–1.5 TW∕cm^2, dichroic microstructures can be written in these nanocomposite materials. The underlying mechanism is transformation of the nanoparticles to prolate shapes. Using a single wavelength, the maximum aspect ratio achievable with this process is limited by partial destruction of particles. Here we show that this limitation can be overcome by simultaneous irradiation with different wavelengths.