THz Heterodyne System Using Novel Mixer and Local Oscillator Devices

We demonstrated a broadband THz heterodyne receiver for astrophysics using Hot-Electron Bolometer (HEB) mixers based on high-T
C
superconducting MgB
2
and Quantum Cascade Laser (QCL) as local oscillator (LO). This detector will advance the state-of-the-art by allowing an operation at elevated temperature $(\sim 20\mathrm{K})$ and providing the intermediate frequency (IF) bandwidth of about 10 GHz. Such a bandwidth is required for high-resolution spectroscopy of interstellar molecular clouds at frequencies 3-5 THz and is not currently available in NbN based HEB mixers. A lab receiver system is being developed to prototype the payload for application on balloons and SmallSats.