Research On Characteristics Of Terahertz Superconducting Tunnel Junction Mixer

SIS(Superconductor-Insulator-Superconductor)mixer has become one of the most important detectors in the terahertz astronomical exploration fields due to its ultra-high sensitivity.Thanks to the advanced thin-film fabrication,superconducting SIS mixers have reached a sensitivity close to quantum limit at the low terahertz frequency band.The main factor affecting the detection performance on the ground is the absorption and reflection of the earth's surroundings,especially the influence of water vapor.Antarctic and space observations are two effective ways to reduce or break through atmospheric constraints.However,such extreme environments often face problems such as lack of power supply and reliability.In order to solve these problems,it is hoped that new SIS mixers capable of operating in a relatively high temperature region can be developed so as to relieve the pressure of refrigeration equipment and achieve excellent performance at the same time.In addition,a large number of advanced instruments and equipment have been deployed in terrestrial astronomical and atmospheric observatories,and the current lack of advanced terahertz astronomical and atmospheric observation instruments severely limits terahertz astronomy and atmospheric science developing in China.Therefore,this paper will focus on the following points: 1)Test of APSOS system to familiarize with and understand the technical requirements of atmospheric science for terahertz receiver systems;2)Constructing a dewar in 8K temperature zone as well as designing and simulating its optical path,in preparation for experimental measurements of high critical temperature SIS detectors;3)Exploring the influence of high-energy particles on the full NbN SIS junction's performance by using a single particle beam irradiation experiment to simulate the high-energy particles environment in the space.The APSOS system tested in this paper has been operated on the Yangbajin observatory in Tibet,China.The single particle beam irradiation experiment simulating the particle environment in the space lays a good foundation for the future research on the feasibility and reliability of space terahertz detection.