512 Signatures of the Higgs model
Computing the signatures of the Higgs model in superconductors in the 5th harmonic generation currents in the non-linear optics In short, indeed the FHG can also be used to detect oscillations with Higgs mode. There are two resonances at Omega=Delta (similar to THG) and for Omega=0.5Delta, which is a new feature. The resonances by a frequency =Delta correspond to a three photon interaction with a respective Higgs mode in the superconductor, while the peaks by 0.5Delta follow from a single photon interacting twice with the same Higgs mode. He also showed, that the emitted signal in the FHG is around a factor 20 smaller than the one in the THG. This comparison was made for the assumption that eA_0 = 1 and in reality FHG and THG intensity will differ by a factor of (eA_0)^2.