The high-frequency limits of SIS receivers

Abstract

The field of submillimeter-wavelength astronomy is blossoming thanks to major investments such as the Atacama Large Millimeter/Submillimeter Array (ALMA) and the Herschel Space Telescope. These projects were enabled by the development of very sensitive receivers, especially those using Superconductor-Insulator-Superconductor (SIS) tunnel junction diodes. Here I review some of the challenges that were faced in pushing this technology from its first demonstrations around 100 GHz to its upper frequency limit beyond 1.2 THz.