Modeling Resonances of Dielectric Spheres in the Terahertz Range

We have studied the resonance properties of dielectric spheres with subwavelength dimensions in the optical and terahertz frequency range. Distribution of the electric field vector in a sphere irradiated by a plane polarized wave has been numerically simulated using the finite element method. The obtained results clearly demonstrate that it is in principle possible to use resonances of various orders in dielectric spheres for the amplification of current in a conducting antenna with dimensions several times smaller than the radiation wavelength. In the case of resonances within short spectral intervals, it is possible to provide a current density gain up to 25-30 dB as compared to that in the absence of a dielectric sphere surrounding the antenna.