Effects of Laser-Annealing on Fixed-Frequency Superconducting Qubits

  1. Hyunseong Kim,
  2. Christian Jünger,
  3. Alexis Morvan,
  4. Edward S. Barnard,
  5. William P. Livingston,
  6. M. Virginia P. Altoé,
  7. Yosep Kim,
  8. Chengyu Song,
  9. Larry Chen,
  10. John Mark Kreikebaum,
  11. D. Frank Ogletree,
  12. David I. Santiago,
  13. and Irfan Siddiqi
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 one case, we observe a two-fold increase in coherence after laser-annealing and perform noise spectroscopy on this qubit to investigate the change in defect features, in particular two-level system defects. 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 first step towards both understanding the underlying physical mechanism and scaling up laser-annealing of superconducting qubits.
arxiv pdf

leave comment