Electrically controlled light scattering

Summary form only given. Electrically controlled switching of light is a key ingredient in modern optical communication and display systems. Up to now such optoelectronic scattering devices do not take advantage of noble metal nanoparticles, which are known to act as strong light scatterers when the frequency of the light is in the spectral range of the particle plasmon resonance. This resonance frequency not only depends on particle properties but also on the refractive index of the surrounding medium. We report on electrically controllable light scattering where electric fields are used to spectrally shift the particle plasmon resonance of spherical noble metal nanoparticles. The basic idea is that the electric field alters the refractive index of the embedding dielectric matrix. For this purpose, spherical noble metal nanoparticles are incorporated in a liquid crystal. An applied electric field aligns the liquid crystal molecules leading to an anisotropic refractive index and thus to a polarization dependent spectral shift of the particle plasmon. Light scattering spectra of an individual gold nanoparticle taken with a dark-field microscope setup are shown.