Technologies for space terahertz intensity interferometry

High angular resolution astronomical observation in terahertz frequencies better than one milli-arcsecond will open a new field of terahertz astronomy. We propose terahertz intensity interferometry for aperture synthesis imaging. Fast photon detectors in terahertz frequencies are the key technology. We work on low leakage SIS photon detectors, which will be capable to detect every photon arrival. Photo response of SIS photon detectors is presented and its application to terahertz intensity interferometry is discussed together with developments of readout electronics and cryogenics.