Dynamic strain measurements in bulk acoustic resonators with stroboscopic x-ray diffraction microscopy*

We report direct observation of gigahertz dynamic strain in a microfabricated bulk-acoustic wave device containing diamond nitrogen-vacancy (NV) centers using stroboscopic scanning hard X-ray diffraction microscopy at the Advanced Photon Source. Color centers, like the NV center, have emerged as an essential platform for quantum sensing and quantum networking. Static lattice strain can tune the spin and orbital Hamiltonians, whereas dynamic strain enables quantum control or hybrid coupling of color centers and a resonator. We image both static and dynamic strain in within an NV center-coupled acoustic resonator with picosecond temporal resolution and nanometer spatial resolution. Our experiments provide a direct view of the diamond strain environment in our devices, which sheds light on their behavior, limitations, and a pathway for improvements. We also correlate the direct strain measurements with spin measurements of the NV centers within these devices.