Topological plasmon polariton on a Dirac magnet helical state: The second harmonic generation enhancement

Abstract

A Dirac magnet, two-dimensional electronic system, can support unidirectional one-dimensional plasmon-polariton excitations propagating along a domain wall of the ferromagnet. The topological plasmon-polariton is characterized by almost linear dispersion and can be an efficient source of the second harmonic generation (SHG) in the broad frequency range. The strong nonlinear response in the system appears due to two reasons: large resonant nonlinear conductivity and broadband phase matching owing to linear dispersion of the carriers. The linear conductivity and nonlinear conductivity responsible for the second harmonic generation were calculated straightforwardly using formalism based on the density matrix approach.