Local trimming of transmon qubit frequency by laser annealing of Josephson junctions*

Limited control in the fabrication of Al-AlOx-Al Josephson junctions makes accurate targeting of the qubit transition frequency in superconducting quantum processors an outstanding challenge. We demonstrate a selective increase in junction resistance by localized thermal annealing using a focused diode laser source at room temperature. By tuning the irradiation time and incident laser power, we controllably increase junction resistance by up to 15%. We quantify the success of this targeting method by comparing transmon qubit transition frequencies and coherence before and after laser annealing.