Cryogeny

To study in detail the coupling between quantum electronic transport and plasmonics, I am developing an on-chip surface plasmon detector based on the kinetic inductance detector (KID) technology used in radio astronomy. These detectors involve microwave superconducting resonators whose inductance varies depending on the flux of detected photons. The goal is to create this type of detector in a superconducting metal that supports plasmonic modes. The plasmons we aim to detect are generated in the aluminum electrodes of a tunnel junction, whose critical superconducting temperature is Tc = 1.2 K. The cryogenic station we are using allows measurements above 3 K, so it is necessary to develop a sub-Kelvin refrigerator to work with aluminum KIDs. With the help of Gilles Guillier (a laboratory engineering assistant), I designed and built a liquid helium-4 refrigerator, which is pumped using an active charcoal pump (Figure below). It allows us to operate for more than 14 hours at a temperature of 880 mK with a stability of 0.3 mK.