A 2-6 THz heterodyne receiver array for SOFIA.

The Institute of Space Sensor Technology of the German Aerospace Research Establishment (DLR) develops a heterodyne array receiver for the frequency range 2 to 6 THz for the Stratospheric Observatory for Infrared Astronomy (SOFIA). Key science issues in that frequency range are the observation of lines of atoms (e.g. [O I]), ions (e.g. [C II], [N II]), and molecules (e.g. OH, HD, CO) with high spectral resolution to study the dynamics and evolution of galactic and extragalactic objects. The first generation receiver will be composed of improved Schottky diode mixers in a 2 by 2 or 4 by 1 array which will be pumped by a gas laser local oscillator. For the second generation receiver new mixers and local oscillator sources are under development. It is expected, that the Schottky diodes will be replaced by hot electron bolometric mixers. As local oscillators solid state p-type Ge and Si lasers are under investigation. The final design goal is an integrated THz array heterodyne receiver. The expected sensitivity and possible applications of the receiver are estimated and compared to other instruments.