Abstract

We investigate the electromagnetic response of anisotropic (non-spherical) copper antimony disulfide (${\rm{CuSb}}{{\rm{S}}_2}$) nanoparticles and layers embedded with them using computational methods. To this end, we calculate the scattering and absorption efficiencies of oblate spheroidal ${\rm{CuSb}}{{\rm{S}}_2}$ nanoparticles using the surface integral equation method. We find strong dependence of the response depending on the anisotropy of the spheroids and their orientation with respect to the electric field polarization of incoming radiation. Thin spheroids display a sharp plasmonic resonance in the ultraviolet, which is observed only for the electric field polarization along the short axis. Fano resonances that appear in the near infrared (NIR) blueshift when the short axis length is reduced, and they can be either strongly suppressed or enhanced depending on the relative orientation of the spheroid. We further investigate the optical response of thin layers containing ${\rm{CuSb}}{{\rm{S}}_2}$ spheroids at a low volume fraction using a Monte Carlo method. We find that the response of these layers can be considerably modified by changing the short axis length and the orientation of particles within the layer with respect to polarization. Our results demonstrate the potential of anisotropic dielectric particles for polarization-dependent-response applications such as solar devices and NIR sensors.

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