Abstract
We have developed a new terahertz (THz) wave detector using an Nb-based superconducting tunnel junction (STJ). The STJ consists of a Nb/Al/AlOx/Al/Nb structure on a single-crystal LiNbO3 substrate. Using LiNbO3 as a substrate, an irradiating THz wave is converted to phonons in LiNbO3, which has a relatively high absorption coefficient. The phonons propagating in the substrate reach the Nb base electrode of the STJ and break Cooper pairs. As a result, the THz wave can be detected as tunneling current signals in the STJ. THz waves from a widely tunable THz-wave parametric oscillator (TPO) were irradiated on to the STJ, which acted as a THz wave detector. The STJs were cooled to an operating temperature of 0.4K using a 3He cryostat. We have observed STJ signals related to THz wave irradiations. In this paper, fabrication processes and characteristics of THz wave detectors using STJs are also discussed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call