Superconducting quantum detectors in YBCO

Stephen M. Wu, Shane A. Cybart, John L. Clarke +1 more

Nathan Bluzer, Martin G. Forrester

A superconducting quantum detector structure in YBCO is described with a directly coupled SQUID read out circuit. The detector geometry is optimized for maximum photoresponse with the use of a serpentine pattern. The serpentine pattern reduces quasiparticle diffusion effects and maximizes the photoinduced changes in the kinetic inductance. The operation of this sensor is analyzed in terms of geometry and quasiparticle lifetime to obtain expressions for the signal and noise of this detector. The background limited infrared performance of this detector is calculated to be about 5/spl times/10/sup -17/ NEP. The photoresponse is expected to be limited by the superconducting energy gap, about 30-40 /spl mu/m.>

Vyacheslav F. Solovyov, Hyunwoo Kim, Paul Farrell

Coplanar (with the ground) and stripline 25 cm long waveguides are manufactured from the YBCO-Kapton material. The waveguides are intended as the key components of a scalable signal delivery for large quantum computing systems and detectors. The waveguide is coupled with an integrated power divider that replaces the standard attenuator. The divider is designed to return most of the power to the previous thermalization stage. The method is projected to reduce the active dissipation by ≈10. We investigate the effect of internal strain in YBCO layer on the device's mechanical stability. We show that adhesives with high stiffness are essential for the reliability of YBCO-Kapton devices.

James F. Annett, Balazs L. Gyorffy, Timothy P. Spiller

Thilo Bauch