Optical Resonances and Enhancement of the Electric Fields in the Gap Between Two Spherical Metallic Nanoparticles

The paper studies the characteristics of the dipole optical nanoantennas which consist of two spherical metallic particles, separated by dielectric gap. The questions connected with the enhancement of the electric fields and with the excitation of the optical resonance are considered. The sizes of nanoparticles, at which the enhancement of the fields by the antenna is maximum, have been found. The frequencies, at which the maximum of the enhancement is reached, have been determined. An influence of material of nanoparticles and environment on the enhancement and frequencies of optical resonances has been analyzed.