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Counting Near Infrared Photons with Microwave Kinetic Inductance Detectors



Jiansong Gao, Michael R. Vissers, Joel N. Ullom, Johannes Hubmayr, Joseph W. Fowler, Leila R. Vale, Weijie Guo


We demonstrate photon counting at 1550~nm wavelength using microwave kinetic inductance detectors (MKIDs) made from TiN/Ti/TiN trilayer films with superconducting transition temperature $T_{c} \sim$ 1.4~K. The detector has a lump-element design with a large interdigitated capacitor (IDC) covered by aluminum and an inductive photon absorber whose volume ranges from 0.4~$\mu$m$^3$ to 20~$\mu$m$^3$. We find that the energy resolution improves as the absorber volume is reduced. We have achieved a energy resolution of 0.22~eV and resolved up to 7 photon per pulse, both greatly improved from previously reported results at 1550~nm wavelength using MKID. Further improvements are possible by optimizing the optical coupling to maximize the photon absorption into the inductive absorber.
Applied Physics Letters


Photon Counting, Microwave Kinetic Inductance Detectors
Created May 22, 2017, Updated January 31, 2018