The Higgs Amplifier

A sudden quench into a superconducting state results in strong Higgs oscillations in the amplitude of the superconducting order parameter. We study theoretically the optical response of a quenched superconductor and find that Higgs modulations lead to a marked enhancement of the reflectance. For strong enough modulations, the reflectance can even exceed unity, corresponding to signal amplification. We discuss possible implications to experiments on light-induced superconductivity in K₃C₆₀.