Correlating Superconducting Qubit Performance Losses to Sidewall Near-Field Scattering via Terahertz Nanophotonics

• URL: http://arxiv.org/abs/2506.04631v1
• Date: Thu, 05 Jun 2025 05:03:37 GMT
• Title: Correlating Superconducting Qubit Performance Losses to Sidewall Near-Field Scattering via Terahertz Nanophotonics
• Authors: Richard H. J. Kim, Samuel J. Haeuser, Joong-Mok Park, Randall K. Chan, Jin-Su Oh, Thomas Koschny, Lin Zhou, Matthew J. Kramer, Akshay A. Murthy, Mustafa Bal, Francesco Crisa, Sabrina Garattoni, Shaojiang Zhu, Andrei Lunin, David Olaya, Peter Hopkins, Alex Romanenko, Anna Grassellino, Jigang Wang,
• Abstract summary: Here, we demonstrate noninvasive terahertz (THz) nano-imaging/spectroscopy of encapsulated niobium transmon qubits.<n>We further employ a THz hyperspectral line scan to probe dielectric responses and field participation at Al junction interfaces.
• Score: 3.5318037110065186
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Elucidating dielectric losses, structural heterogeneity, and interface imperfections is critical for improving coherence in superconducting qubits. However, most diagnostics rely on destructive electron microscopy or low-throughput millikelvin quantum measurements. Here, we demonstrate noninvasive terahertz (THz) nano-imaging/-spectroscopy of encapsulated niobium transmon qubits, revealing sidewall near-field scattering that correlates with qubit coherence. We further employ a THz hyperspectral line scan to probe dielectric responses and field participation at Al junction interfaces. These findings highlight the promise of THz near-field methods as a high-throughput proxy characterization tool for guiding material selection and optimizing processing protocols to improve qubit and quantum circuit performance.

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