Gigahertz frequency diamond opto-mechanical crystals for hybrid quantum systems

Diamond mechanical systems in the quantum regime provide many exciting opportunities in quantum sensing, networking, and computing. Diamond combines superb mechanical and thermal properties with highly coherent embedded defect-based qubits, such as the nitrogen vacancy (NV) center and silicon vacancy (SiV) center. Here I present high-quality-factor, high-frequency, diamond optomechanical resonators with embedded defect centers. We measure mechanical quality factors as high as 250,000 and optical quality factors up to 43,000 at dilution refrigerator temperatures. We characterize the optomechanical coupling in these devices and measure vacuum optomechanical coupling rates as high as 250 kHz. The corresponding optomechanical cooperativities of ~ 10 allow the use of optomechanical backaction to cool these devices to their quantum ground state of mechanical motion - an important requirement for using them in several quantum information and sensing applications.