Millimeter and submillimeter wave detection and mixing with superconducting weak links

A weak link between two bulk superconductors can exhibit Josephson effects and can be used as a fast sensitive detector or mixer for electromagnetic radiation. Emphasis is placed on the millimeter and submillimeter range where such applications are potentially most important, though such devices should also work well at lower frequencies. The peculiar properties of the weak link make possible a variety of modes of operation including one in which it is both local oscillator and mixer. These modes of operation are analyzed and the pivotal experiments are reviewed. Noise and impedance matching are considered and comparison is made with other types of detectors of millimeter and submillimeter waves.