A Wideband Balun-Based Microwave Device for Quantum Information Processing With Nitrogen–Vacancy Centers in Diamond

We present a wideband balun-based microwave device for quantum manipulation of nitrogen-vacancy centers in diamond. The device employs a balun with multi-section Chebyshev impedance transformer to realize the conversion from the unbalanced feed line to the balanced feed line and ensures impedance matching. A bandwidth of 2.2 GHz with the maximum resonance frequency up to 4.4 GHz has been realized, which is important for multi-qubit quantum control of the nitrogen-vacancy centers. We also carry out optically detected magnetic resonance to observe Rabi oscillations and calibrate the strength of the microwave magnetic field generated by the microwave device. With an input power of 0.5 W, the Rabi frequencies can reach 6.17 MHz and 6.06 MHz for resonant microwave at 1.40 GHz and 4.34 GHz, respectively. Combining with large bandwidth and excellent magnetic field homogeneity, the device can be applied in solid-state quantum information processing.