As superconducting quantum processors increase in complexity, techniques to overcome constraints on frequency crowding are needed. The recently developed method of laser-annealing provides an effective post-fabrication method to adjust the frequency of superconducting qubits. Here, we present an automated laser-annealing apparatus based on conventional microscopy components and demonstrate preservation of highly coherent transmons. In addition, we perform noise spectroscopy to investigate the change in defect features, in particular, two-level system defects, after laser-annealing. Finally, we present a local heating model as well as demonstrate aging stability for laser-annealing on the wafer scale. Our work constitutes an important step toward both understanding the underlying physical mechanism and scaling up laser-annealing of superconducting qubits.
Effects of laser-annealing on fixed-frequency superconducting qubits
Hyunseong Kim, Christian Jünger, Alexis Morvan, Edward S. Barnard, William P. Livingston, M. Virginia P. Altoé, Yosep Kim, Chengyu Song, Larry Chen, John Mark Kreikebaum, D. Frank Ogletree, David I. Santiago, Irfan Siddiqi; Effects of laser-annealing on fixed-frequency superconducting qubits. Appl. Phys. Lett. 3 October 2022; 121 (14): 142601. https://doi.org/10.1063/5.0102092
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