Stabilized hot electron bolometer heterodyne receiver at 2.5?THz

We report on a method to stabilize a hot electron bolometer (HEB) mixer at 2.5 THz. The technique utilizes feedback control of the local oscillator (LO) laser power by means of a swing-arm actuator placed in the optical beam path. We demonstrate that this technique yields a factor of 50 improvement in the spectroscopic Allan variance time which...

Performance of the flight model HIFI band 3 and 4 mixer units

We describe the performance of the Band 3 and Band 4 Flight Model mixer units for Herschel/HIFI Instrument. These units are part of the Focal Plane Unit of HIFI. The band 3 and 4 mixer units cover the 800-960 GHz and 960-1120 GHz frequency range and have a 4-8 GHz IF frequency band. The sensitivities of the mixers within the HIFI setting are...

Niobium titanium nitride-based superconductor-insulator-superconductor mixers for low-noise terahertz receivers

Integrating NbTiN-based microstrip tuning circuits with traditional Nb superconductor-insulator-superconductor (SIS) junctions enables the low-noise operation regime of SIS mixers to be extended from below 0.7?to?1.15?THz. In particular, mixers incorporating a NbTiN/SiO2/NbTiN microstrip tuning circuit offer low-noise performance below 0.8–0.85...