Plasmon-induced terahertz radiation generation due to symmetry breaking in a nonlinear metallic nanodimer

We suggest an alternative way of terahertz radiation generation utilizing the effect of spontaneous symmetry breaking in a nonlinear metallic nanodimer illuminated by light. We show that the symmetry breaking is caused by instability of plasmon eigenmodes of the system and can lead either to spontaneous magnetization of the dimer or to a periodic self-modulation regime of light scattering. We find that the modulation frequency lies in the terahertz band and may be tuned within a wide range.