Acoustic field induced nonlinear magneto-optical rotation in a diamond mechanical resonator
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-05-18 |
| Journal | Scientific Reports |
| Authors | Mohsen Ghaderi Goran Abad, Fatemeh Ashrafizadeh Khalifani, Mohammad Mahmoudi |
| Institutions | University of Zanjan |
| Citations | 2 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a novel method for achieving highly efficient, nonlinear Magneto-Optical Rotation (MOR) using acoustic strain fields coupled to Nitrogen-Vacancy (NV) centers embedded in a Diamond Mechanical Resonator (DMR).
- Core Innovation: MOR is enhanced and controlled by inducing birefringence via the cross-Kerr effect, mediated by an acoustic strain field acting on the NV centerâs spin-triplet ground state (3A).
- Performance Metric: Achieved complete polarization rotation (90 degrees) of a linearly polarized microwave probe field.
- Efficiency: High transmission intensity (Ty up to 0.91) is maintained simultaneously with the 90° rotation, indicating minimal loss.
- Control Mechanism: The MOR angle is highly sensitive and tunable via three external parameters: the static magnetic field (Zeeman splitting), the intensity of the acoustic strain field (Ωs), and the relative phase (Ί) between the applied fields.
- Physical Mechanism: The nonlinear cross-Kerr effect, driven by the acoustic field, is identified as the primary mechanism responsible for enhancing the MOR angle beyond the 45 degrees achievable by linear response alone.
- System Architecture: A three-level closed-loop quantum system is established in the NV center ground states, where the acoustic field couples the electric dipole forbidden transition.
- Value Proposition: Provides a robust, solid-state platform for polarization control, suitable for integration into micro-scale devices.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| NV Center Ground State | 3A (Spin Triplet) | N/A | Electronic structure |
| Zero-Field Splitting (D) | 2.87 | GHz | Energy gap between ms=0 and ms=±1 states |
| Maximum MOR Angle | 90 | degrees | Achieved at probe field resonance (Îp=0) |
| Maximum Transmission (Ty) | 0.91 | N/A | Normalized intensity of the rotated (Ć·-direction) probe field |
| Static Magnetic Field (ÎB) | 17Î (or ~2 Gauss) | N/A (Scaled by Î) | Value used to achieve maximum MOR |
| Acoustic Field Rabi Frequency (Ωs) | 17Î | N/A (Scaled by Î) | Intensity required for maximum MOR enhancement |
| Probe Field Rabi Frequency (Ωp) | 0.01Î | N/A (Scaled by Î) | Weak probe field condition |
| Scaling Factor (Î) | 2.2 | MHz | Spontaneous emission/dephasing rate (Î31=Î32=Î3d) |
| Absorption Coefficient (αl) | 107Î | N/A (Scaled by Î) | Length and density factor optimized for maximum Ty |
| Coherence Time | Long | N/A | Key property of NV centers in diamond at room temperature |
| Polarization Rotation Mechanism | Birefringence (Dispersion Difference) | N/A | Dominant effect over dichroism (absorption difference) |
Key Methodologies
Section titled âKey MethodologiesâThe study relies on establishing and modeling a three-level closed-loop quantum system within the NV center ground states (ms=0, ms=±1) of a high-Q single-crystal DMR.
- System Preparation: A Diamond Mechanical Resonator (DMR) containing many embedded NV centers is used. The NV center ground state degeneracy (ms=±1) is lifted by applying a static magnetic field (Faraday geometry), inducing Zeeman splitting (ÎB).
- Strain Field Generation: An acoustic strain field is generated by vibrating the DMR via an attached piezoelement, modeling the strain as an effective electric field.
- Closed-Loop Coupling: The acoustic strain field coherently couples the electric dipole forbidden transition (|2> â |3>), completing the closed-loop configuration in the ground states.
- Probe Field Interaction: A linearly polarized microwave probe field (Ep) is applied, consisting of right- and left-circular components (Ωp+, Ωp-) that drive the allowed transitions (|1> â |3> and |2> â |3>).
- Theoretical Modeling: The system dynamics are governed by the Hamiltonian in the rotating wave and dipole approximations, solved using the von Neumann density matrix equations.
- Susceptibility Calculation: Normalized susceptibilities (S±) for the circular components are calculated. The difference between the real parts (Re[S+] - Re[S-]) quantifies the induced birefringence, which is the primary driver of MOR.
- MOR Quantification: The intensity of the transmitted field in the rotated (Ʒ) direction (Ty) and the primary (x) direction (Tx) are calculated to determine the MOR angle (Ί = arctan[sqrt(Ty/Tx)]).
Commercial Applications
Section titled âCommercial ApplicationsâThe ability to achieve complete, controllable polarization rotation in a solid-state diamond platform makes this technology highly relevant for several engineering and quantum fields.
- Optical Communication:
- Efficient polarization converters for switching between Transverse Electric (TE) and Transverse Magnetic (TM) modes in integrated optical circuits.
- Quantum Sensing and Metrology:
- High-sensitivity magnetometry, leveraging the strong dependence of MOR on the static magnetic field (Zeeman splitting).
- Precision measurements, utilizing the sensitivity of the MOR angle to external fields (strain, phase).
- Lidar Systems:
- Depolarization backscattering lidar, where controlled polarization manipulation is essential for atmospheric sensing.
- Polarization Spectroscopy:
- Advanced spectroscopic techniques requiring precise control and measurement of polarization rotation and birefringence.
- Quantum Information Processing:
- Utilizing the NV centerâs long coherence time and controlled spin dynamics for quantum memory and qubit manipulation.
View Original Abstract
Abstract We study the nonlinear magneto-optical rotation (MOR) of a linearly polarized microwave probe field passing through many nitrogen-vacancy (NV) centers embedded in a high-Q single-crystal diamond mechanical resonator. On the basis of the strain-mediated coupling mechanism, we establish a three-level closed-loop system in the ground states of the NV center in the presence of a static magnetic field. It is shown that by applying an acoustic field, the birefringence is induced in the system through the cross-Kerr effect, so that the probe field is transmitted with a high intensity and rotated polarization plane by 90 degrees. In addition, we demonstrate that the acoustic field has a major role in enhancing the MOR angle to 90 degrees. Moreover, it is shown that the MOR angle of the polarization plane after passing through the presented system is sensitive to the relative phase of the applied fields. The physical mechanism of the MOR enhancement is explained using the analytical expressions which are in good agreement with the numerical results. The presented scheme can be used as a polarization converter for efficient switching TE/TM modes in optical communication, the depolarization backscattering lidar, polarization spectroscopy and precision measurements.