Response properties at 2.525 terahertz using high-T/sub c/ Josephson junctions on silicon bicrystal substrates

Using high-T/sub c/ grain boundary Josephson junctions (GBJJs) made of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// deposited across silicon bicrystal boundary, we successfully demonstrated direct response at frequency as high as 2.525 THz and the operation temperature up to 70 K. Also, the effects of response on polarization of electromagnetic waves and the harmonic mixing properties are investigated. It is found that there is no polarization dependence of the response for our high-quality GBJJs. This result is favorable to the spectroscopy application. At frequency as high as 2.525 THz, the high-order harmonic mixing at zero and finite bias voltage has been demonstrated.