Superconducting THz emitters and receivers in YBCO utilizing focused helium beam nano-lithography

There exists an under-utilized portion of the electromagnetic spectrum, located between the microwave and infrared wavelengths, in the sub-millimeter band.This region, known as terahertz radiation, has historically been problematic to access.There have been numerous demonstrations of THz electronics using LTS Josephson junctions that provide precise frequency control and on-chip detection via the AC Josephson effect.Unfortunately, the mature technology of niobium Josephson junction fabrication imposes an upper frequency cutoff of about 0.75 THz, a fundamental limit defined by the superconducting energy gap in niobium.HTS materials can have energy gaps greater than 40 mV which may allow for frequencies above 10 THz and provide a solution that can cover the entire 1.010 THz band.More reliable fabrication methods of HTS Josephson junctions have metallic diffusive Josephson barriers that preclude use at THz frequencies.Recently, one of us has demonstrated a new, scalable, nanomanufacturing method of HTS devices utilizing a focused helium ion beam to directly write junctions into a commercially grown HTS thin film. Here, we propose to research and develop HTS emitters and receivers of THz radiation using this low-cost manufacturing technique.