Copper Waveguide Cavities with Reduced Surface Loss for Coupling to Superconducting Qubits

Daniela F. Bogorin, Doug T. McClure, Matthew Ware, B. L.T. Plourde

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Significant improvements in superconducting qubit coherence times have been achieved recently with 3-D microwave waveguide cavities coupled to transmon qubits. While many of the measurements in this direction have utilized superconducting aluminum cavities, other recent work has involved qubits coupled to copper cavities with coherence times approaching 0.1 ms. The copper provides a good path for thermalizing the cavity walls and qubit chip, although the substantial cavity loss makes conventional dispersive qubit measurements challenging. We are exploring various approaches for improving the quality factor of 3-D copper cavities, including electropolishing and coating with superconducting layers of tin. We have characterized these cavities on multiple cooldowns and found tin plating to be robust. In addition, we have performed coherence measurements on transmon qubits in these cavities and observed promising performance.

Original languageEnglish (US)
Article number6846295
JournalIEEE Transactions on Applied Superconductivity
Issue number4
StatePublished - Aug 1 2014


  • 3-D cavity resonators
  • Cavity quality factor
  • cQED
  • superconducting qubits
  • transmon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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