Description: The goal is to develop a high temperature superconductor Josephson mixer for THz high resolution spectroscopy. A factor of 4-5 improvement over state of the art at 2 THz compared to other low temperature detectors is expected. The junction parameters do not degrade with temperature until above 50 K means that these detectors should be more than an order of magnitude mores sensitive then available detectors for planetary missions requiring passively cooled instruments. This could be significant in enabling high resolution THz spectroscopy planetary bodies from a nearby orbit (for example comets). High Temperature Superconducting (YBCO) Josephson Junctions have historically had poor performance and reproducibility. This work is enabled by the junction fabrication process developed by a group at UCR, utilizing a focus beam of He ions (beam diameter ~1 nm) to directly write the Josephson barrier into junctions. This method enables precise tuning of the junctions which made Josephson mixers difficult to match into microwave circuits in the past. The mixers have a large IF bandwidth and the nanometer scale junctions will require only nanowatts of local oscillator power, important to move to large focal plane arrays of detectors.

Benefits: Utilize the data taken in CIF19 to optimize devices for record sensitivities under certain conditions.