Nonlinear effects in the Josephson-vortex terahertz photonic crystal

Analysis has been made of the amplitudes of the second and third harmonics when pumping a discrete frequency to the Josephson-vortex photonic crystal within the THz range of the electromagnetic spectrum. The results of numerical simulations show that there are certain resonance frequencies for these harmonics where the amplitudes are strongly enhanced. The frequencies at which these resonances occur can be tuned by an applied magnetic field and tilting the material with respect to the incident radiation. For the second harmonic it has been possible to describe these resonances analytically with a resonance approximation which displays good agreement with numerical simulations at and near the resonances. A similar perturbative method has been used to simulate the nonlinear mixing of two discrete THz frequencies in the JV photonic crystal, producing resonances for harmonics at the sum and the difference of these two input frequencies. This method can allow a high degree of control over the harmonic frequencies produced.