Electromagnetic-Induced Currents in a Triangular Cluster of Nanospheres

A plane cluster of subwavelength particles located at the vertices and center of a regular triangle is considered. Only the central particle is excited by external electromagnetic radiation. Formulas for self-consistent currents induced in particles as a result of mutual particle interactions by their near fields are derived. Calculations have shown that the currents in the peripheral particles and the central one can be co- or counter-directed, depending on the packing density of the particles when the central particle is excited at the resonant frequency of the simplest cluster in the form of a dimer. Oscillations in the sign of currents in particles caused by changes in packing density are smoothed out and completely disappear when excited at a frequency below the resonant frequency, and, on the contrary, increase at excitation frequencies exceeding the resonant one.