Microwave control of the superconducting proximity effect and minigap in magnetic and normal metals

We demonstrate theoretically that shining light on superconducting proximity structures controls the minigap and triplet proximity effect in normal and magnetic metals, respectively. Considering both a bilayer and Josephson junction geometry, we show that microwave irradiation with frequency $\omega$ qualitatively alters the spectral properties of the system, controlling the minigap size $E_\text{mg}$ and even replacing the minigap with a strong peak of quasiparticle accumulation at zero energy when $\omega=E_\text{mg}$. The interaction between light and Cooper pairs may thus open a route to active control of quantum coherent phenomena in superconducting proximity structures.