Orbital State Manipulation of a Diamond Nitrogen-Vacancy Center Using a Mechanical Resonator

We study the resonant optical transitions of a single nitrogen-vacancy (NV) center that is coherently dressed by a strong mechanical drive. Using a gigahertz-frequency diamond mechanical resonator that is strain coupled to a NV center’s orbital states, we demonstrate coherent Raman sidebands out to the ninth order and orbital-phonon interactions that mix the two excited-state orbital branches. These interactions are spectroscopically revealed through a multiphonon Rabi splitting of the orbital branches which scales as a function of resonator driving amplitude and is successfully reproduced in a quantum model. Finally, we discuss the application of mechanical driving to engineering NV-center orbital states.

Figure 1

(a) Device geometry and structure of a NV center inside a diamond unit cell (blue cube). A uniaxial stress wave is generated through the top zinc oxide transducer. Microwave antenna on the bottom provides magnetic manipulation of a NV-center spin. (b) NV-center excited-state and ground-state level diagrams as a function of transverse strain. Experimental data (black dots) show excellent agreement with Ref. [19]. (c) PLE sequence for phonon-dressed state measurement. (d) PLE spectrum of a single NV center with 10.6 GHz static strain splitting between $E_x$ and $E_y$ states (blue curve). A $32\mu \mathrm{W}$ drive to the transducer excites phonon sideband transitions (red curve).

Figure 2

(a) PLE spectrum of NV1 with $\{|E_x⟩,|E_y⟩\}$ state splitting of 10.6 GHz in the absence of mechanical driving. (b) Phonon-dressed state PLE measurement with ${\omega }_m/2\pi =1.3844\mathrm{GHz}$. The mechanical driving amplitude is proportional to square root of the power applied to the transducer, $P^{1/2}$. Sideband transitions and level repulsion are evident in between $E$ states. (c) Reconstruction of experimental data through quantum master equation simulation. (d) $E_x$ sideband transition ($n=0$ to 8) photoluminescence peak amplitude (solid dots) plotted against theoretical prediction (solid line), which is not a fit to the data.

Figure 3

(a) PLE scan of NV2, which has an $\{|E_x⟩,|E_y⟩\}$ state splitting of 3.2 GHz. (b) Experimental data from phonon-dressed state PLE. The mechanical driving frequency, ${\omega }_m/2\pi =1.6\mathrm{GHz}$, matches half of the $\{|E_x⟩$, $|E_y⟩\}$ splitting. The dressed orbital states exhibit gigahertz-scale phonon Rabi splitting, which is well described by the $n=1$ term in Eq. (4), ${\mathcal{E}}_1\sin 2\theta J_1\{2[{\mathcal{E}}_1/(\hslash {\omega }_m)]\cos 2\theta \}$, which corresponds to a 2-phonon Rabi splitting (white dashed lines). (c) Reconstruction of experimental data with a quantum master equation simulation.

Figure 4

(a) PLE scan of NV3 with $\{|E_x⟩,|E_y⟩\}$ state splitting of 2.1 GHz, taken with continuous wave 2.877 GHz magnetic microwave driving to the antenna. (b) Experimental data from phonon-dressed state PLE measurement of NV3 with ${\omega }_m/2\pi =1.3844\mathrm{GHz}$. A Rabi splitting of 0.93 GHz in the $|A_2⟩$ state is observed with 10 mW mechanical driving. (c) Reconstruction of experimental data using a quantum master equation simulation.