Discovery of Terahertz Second Harmonic Generation from Lightwave Acceleration of Symmetry--Breaking Nonlinear Supercurrents

C. Vaswani, C. Sundahl, M. Mootz +11

We report terahertz (THz) second harmonic generation (SHG) in superconductors (SC) with inversion symmetric equilibrium states that forbid even-order nonlinearities. Such SHG signa…