Analysis of the phonon-polariton response of silicon carbide microparticles and nanoparticles by use of the boundary element method

We investigate the small-particle phonon-polariton response of several microstructures that are made of silicon carbide (SiC). Phonon polaritons can be excited in a wavelength region between 10 and 12 µm. Simple structures such as elliptical cylinders support phonon polaritons at two wavelengths, which depend on the axis ratio of the particle. In particles with a more irregular shape such as rectangular or triangular cylinders, up to five phonon polaritons can be excited. Through comparison of the strength of phonon-polariton excitation with the similar effect of the plasmon-polariton excitation in metallic nanoparticles, it is found that the excitation of phonon polaritons is more efficient. This behavior is attributed to the lower imaginary part of the dielectric constant of SiC.