Amplitude modulation of proximity effect weak links

By a careful examination of the size of the microwave induced step structure in the dc current-voltage (I-V) characteristic of proximity effect weak links at low frequency (<4 GHz), it has been determined that the amplitude of the microwave Josephson current decreases exponentially with increasing voltage. This amplitude modulation of the Josephson effect depends on the magnitude of both the rf and dc voltages and is interpreted in terms of voltage induced pair breaking within the link rather than thermal heating. Application of this effect to produce a three terminal Josephson device is introduced.