Thein Oo

Optomechanical quantum control of a nitrogen vacancy center in diamond

We demonstrate optomechanical quantum control of a nitrogen vacancy (NV) in the resolved-sideband regime by coupling the NV to both optical fields and surface acoustic waves and by using strong excited-state electron-phonon coupling for NVs.

Coupling a Surface Acoustic Wave to an Electron Spin in Diamond via a Dark State

The emerging field of quantum acoustics explores interactions between acoustic waves and artificial atoms and their applications in quantum information processing. In this experimental study, we demonstrate the coupling between a surface acoustic wave (SAW) and an electron spin in diamond by taking advantage of the strong strain coupling of the excited states of a nitrogen vacancy center, while avoiding the short lifetime of these states. The SAW-spin coupling takes place through a lamda-type three-level system where two ground spin states couple to a common excited state through a phonon-assisted as well as a direct dipole optical transition. Both coherent population trapping and optically-driven spin transitions have been realized. The coherent population trapping demonstrates the coupling between a SAW and an electron spin coherence through a dark state. The optically-driven spin transitions, which resemble the sideband transitions in a trapped ion system, can enable the quantum control of both spin and mechanical degrees of freedom and potentially a trapped-ion-like solid state system for applications in quantum computing. These results establish an experimental platform for spin-based quantum acoustic, bridging the gap between spintronics and quantum acoustics.

Transfer of Phase Information between Microwave and Optical Fields via an Electron Spin

We demonstrate the coherent coupling and the resulting transfer of phase information between microwave and optical fields in a single nitrogen vacancy center in diamond. The relative phase of two microwave fields is encoded in a coherent superposition spin state. This phase information is then retrieved with a pair of optical fields. A related process is also used for the transfer of phase information from optical to microwave fields. These studies show the essential role of dark states, including optical pumping into the dark states, in the coherent microwave-optical coupling and open the door to the full quantum state transfer between microwave and optical fields in a solid-state spin ensemble.

Coherent Optomechanical Coupling between a Surface Acoustic Wave and a Nitrogen Vacancy Center in Diamond

We demonstrate coherent coupling between a surface acoustic wave and a nitrogen vacancy center in diamond in the resolved-sideband regime. Rabi oscillations and coherent population trapping have been demonstrated via phonon-assisted sideband transitions.