We propose an effective optical approach to monitor superconductors in a two-layer superconductor-normal metal structure. Effectively, such a hybrid system represents a resonator, where electrons are strongly coupled with light. We show that the interaction of light with the superconductor is strongly boosted in the presence of the neighboring metal and, as a result, the electromagnetic power absorption of the system is dramatically enhanced. It manifests itself in a giant Fano-type resonance which can uniquely characterize the elementary excitations of the system. Our approach is especially promising for topological superconductors, where Majorana fermions could be revealed and controlled by light.

• Received 27 April 2018
• Revised 13 July 2018

DOI:https://doi.org/10.1103/PhysRevB.98.064502