We show that transport through a superconducting quantum point contact biased at subgap voltages is strongly affected by a microwave field. The subgap current is increased by several orders of magnitude. Quantum interference among resonant scattering events involving photon absorption is reflected as an oscillating structure in the I-V curve. We also discuss how the same interference effect can be applied for detecting weak electromagnetic signals up to the gap frequency, and how it is affected by dephasing and relaxation.
@article{arxiv.cond-mat/9905386,
title = {Microwave controlled phase coherent transport in mesoscopic S-N-S structures},
author = {N. I. Lundin and L. Y. Gorelik and R. I. Shekhter and V. S. Shumeiko and M. Jonson},
journal= {arXiv preprint arXiv:cond-mat/9905386},
year = {2007}
}