THz Hot-Electron Bolometer mixers

We overview the technology of superconducting Hot-Electron Bolometer mixers in the field of terahertz heterodyne detection. HEB mixer performance is analyzed vs competing technologies and application fields, with emphasize on radio astronomy. We discuss materials which have been reported in the past to be used for such devices with both phonon-substrate and electron-diffusion cooling mechanisms. It caused a splash of interesting theories with attempts of describing both dc and RF characteristics of HEB mixers. Development of HEB mixers made possible to extend high spectral resolution radio astronomy beyond 1THz.