Fabrication of stable Josephson point contacts for submillimetre-wavelength mixers

Abstract
A technique for fabricating stable, recyclable Josephson point contacts is described. The niobium contact wires are enclosed in a glass encapsulation which is thermally matched in expansion to the wires. The devices are primarily intended for operation at submillimetre wavelengths. A demonstration of their use as harmonic mixers for frequency metrology is described involving 49th harmonic mixing at 0.89 THz (0.337 mm wavelength).