Coherent control of solid-state defect spins via patterned boron-doped diamond circuit

We demonstrate the coherent control of nitrogen-vacancy (NV) spins using an electronic circuit integrated within diamond: a patterned, conductive boron-doped diamond (BDD) microwave waveguide. First, we validate the high-frequency performance of the circuit by characterizing its impedance up to the microwave range, confirming microwave transmission sufficient for optically detected magnetic resonance (ODMR) and coherent Rabi control. Under ambient conditions, we perform ODMR and observe Rabi oscillations driven by the heavily doped BDD circuit. We verify that microwave-induced frequency shifts remain limited under the present operating conditions at room temperature. In addition, separate high-pressure and low-temperature continuous-wave ODMR measurements demonstrate that the BDD antenna remains operational as a microwave delivery element in a high-pressure and low-temperature environment. These results indicate the potential of BDD circuits for on-chip microwave delivery in NV-based quantum devices, particularly for ODMR operation under extreme conditions.