Characterization of Microwave Loss Using Multimode Superconducting Resonators
Chan U Lei, Suhas Ganjam, Lev Krayzman, Archan Banerjee, Kim Kisslinger, Sooyeon Hwang, Luigi Frunzio, Robert Schoelkopf
Abstract
Understanding the loss mechanisms in materials is crucial to improving coherence in superconducting quantum circuits. The authors present a technique based on multimode superconducting resonators that distinguishes and quantifies all loss channels in relevant materials. Applying this technique reveals that both chemical etching and diamond turning reduce surface losses in high-purity aluminum, while coating diamond-turned surfaces with thin-film aluminum significantly improves joint quality. This method can be used to design on-chip superconducting devices to characterize microwave losses, as well as to quantify the effects of fabrication processes.