Photon-activated switch behavior in the single-electron transistor with a superconducting island

Abstract

We show that the effects of photon-assisted tunneling in the single-electron transistor are dramatically enhanced if the mesoscopic island is superconducting. Many electrons can tunnel through the system for each absorbed photon as a result of an even-odd electron number effect in the superconducting island. For suitable bias, the device acts as a photon-activated switch from a low- to a high-current state, providing a sensitive mechanism for microwave detection. A simple model quantitatively describes this particular consequence and other less dramatic effects of microwave radiation.