Hybrid continuous dynamical decoupling - a photon-phonon doubly dressed spin
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-02-09 |
| Journal | Journal of Optics |
| Authors | Jean Teissier, Arne Barfuss, Patrick Maletinsky |
| Institutions | University of Basel |
| Citations | 18 |
| Analysis | Full AI Review Included |
Hybrid Continuous Dynamical Decoupling in SCD Diamond: Technical Analysis and 6CCVD Material Solutions
Section titled âHybrid Continuous Dynamical Decoupling in SCD Diamond: Technical Analysis and 6CCVD Material SolutionsâThis document summarizes the technical achievements presented in the paper âHybrid continuous dynamical decoupling: a photon-phonon doubly dressed spinâ and provides corresponding material solutions offered by 6CCVD, an expert provider of MPCVD diamond for quantum applications.
Executive Summary
Section titled âExecutive SummaryâThe research demonstrates a novel Hybrid Continuous Dynamical Decoupling (HCDD) scheme using a single Nitrogen-Vacancy (NV) electronic spin coupled parametrically to a diamond mechanical resonator (cantilever).
- Coherence Enhancement: The HCDD method, combining resonant microwave (photon) driving and parametric strain (phonon) driving, successfully protects the NV spin from low-frequency environmental noise.
- Three Orders of Magnitude Improvement: The Rabi oscillation decay time (TRabi) was extended by nearly three orders of magnitude, from a baseline of 5.3 ± 0.2 ”s (Gaussian decay) to 2.9 ± 0.3 ms (exponential decay).
- Decoupling Mechanism: Second-order dynamical decoupling is achieved by transducing the second driving field through the mechanical resonator, which acts as a low-pass filter for amplitude noise, yielding highly stable field amplitude.
- Doubly Dressed States: The technique successfully creates spin eigenstates doubly dressed by both microwave photons and cantilever phonons.
- Material Purity Requirement: The experiment relies on ultra-pure, single-crystal synthetic diamond substrates suitable for low-density (< 1 ”m-2) 14N implantation and high-quality top-down nanofabrication.
- Pathway to Tâ Limit: The authors identify that future work requires high quality-factor (Q â„ 106) mechanical oscillators, achievable in ultra-pure SCD under vacuum, to reach the ultimate spin relaxation limit (Tâ â 5.1 ms).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Spin Relaxation Time (Tâ) | 5.1 ± 0.8 | ms | Fundamental limit of coherence (Undriven NV) |
| Initial Rabi Decay Time (TRabi) | 5.3 ± 0.2 | ”s | Baseline coherence time (Gaussian decay) |
| HCDD Rabi Decay Time (TRabi) | 2.9 ± 0.3 | ms | Coherence protected by HCDD (Exponential decay) |
| Dressed State Coherence (T2,d.d.) | â„ 100 | ”s | Improved from typical Tâ â 2 ”s |
| Cantilever Mode Frequency (Ïm/2Ï) | 5.81 | MHz | Fixed resonance frequency used for parametric drive |
| Zero-Field Splitting (Dâ) | 2.87 | GHz | NV center (ground state sublevels) |
| Parallel Strain Coupling Strength (d||) | ~ 5.5 | GHz/strain | Coupling between NV spin and mechanical motion |
| Mechanical Quality Factor (Q) | â 530 | (unitless) | Measured under ambient conditions |
| Target Q for Tâ Limit | â„ 106 | (unitless) | Required under vacuum for maximum Tâ |
Key Methodologies
Section titled âKey MethodologiesâThe experiment successfully combined high-fidelity quantum control with nanofabricated diamond mechanics using the following key steps:
- Material Selection & Preparation:
- Use of ultra-pure, single-crystal, synthetic diamond grown via MPCVD.
- Creation of NV centers via low-density (less than 1 ”m-2) 14N ion implantation followed by high-temperature annealing.
- Nanofabrication:
- Top-down fabrication of singly-clamped cantilever mechanical resonators from the SCD substrate.
- Mechanical Actuation:
- A nearby piezoelectric transducer was used to actuate the diamond cantilever, generating time-varying (AC) strain fields along the NV binding axis (z) for parametric driving.
- First Order Decoupling (Photon Drive):
- Coherent, resonant microwave (MW) magnetic fields were applied transverse to the NV axis to drive the |0ă â |-1ă transition, achieving first-order continuous dynamical decoupling.
- Second Order Decoupling (Phonon Drive):
- Parametric strain drive, generated by the mechanical resonator, was applied along the quantisation axis (z).
- This spin-oscillator interaction decoupled the spin from amplitude fluctuations in the microwave field, achieving concatenated, hybrid continuous dynamical decoupling (HCDD).
- Readout:
- Spin dynamics were studied using a homebuilt confocal microscope, employing green optical illumination for initialization and detection of red NV fluorescence for readout.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical reliance of advanced hybrid quantum systems on exceptionally high-quality, custom-engineered diamond materials. 6CCVD is uniquely positioned to supply the materials required to replicate, scale, and surpass the results achieved in this study.
Applicable Materials for Hybrid Quantum Systems
Section titled âApplicable Materials for Hybrid Quantum SystemsâTo achieve long coherence times and high mechanical quality factors (Q), the research necessitates low-strain, ultra-pure diamond.
| 6CCVD Material | Relevance to Paperâs Requirements | Material Specifications |
|---|---|---|
| Optical Grade SCD (Single Crystal Diamond) | REQUIRED. Used for the high-Q mechanical resonators and host material for NV centers. Ultra-low nitrogen content is critical for minimizing spin noise and maximizing Tâ and Tâ. | SCD plates up to 1-inch size. Custom thickness control (0.1”m - 500”m) ideal for thin-film, high-Q cantilever fabrication. |
| Low Strain SCD Substrates | REQUIRED. High mechanical Q factors (Q â„ 106 demonstrated elsewhere) demand substrates with minimal intrinsic crystalline strain, ensuring stable resonator performance. | Guaranteed high crystalline quality, verified by internal optical and strain metrology. |
| Metalized SCD/PCD | ENHANCEMENT. Although not detailed for coupling in this paper, efficient MW driving often requires on-chip striplines or antennas. | Custom metalization capabilities (Au, Pt, Pd, Ti, W, Cu) available for integrating RF components directly onto the diamond surface. |
Customization Potential
Section titled âCustomization PotentialâThe fabrication of high-fidelity nanomechanical devices requires extremely precise material specifications and post-processing, which 6CCVD provides:
- Thickness Control: The researchers relied on top-down nanofabrication to create cantilevers. 6CCVD provides SCD plates with exceptional thickness uniformity from 0.1 ”m up to 500 ”m, enabling highly repeatable etching processes and precise control over resonator mass and stiffness.
- Custom Polishing: The base of the cantilever requires a highly smooth surface for optimal lithography. 6CCVD provides ultra-low surface roughness:
- SCD: Ra < 1 nm (essential for high-resolution patterning).
- Large Format Manufacturing: While this paper focuses on single-NV devices, scaling requires larger substrates. 6CCVD offers large-area PCD (up to 125mm) and custom-sized SCD plates for high-throughput fabrication of arrays of diamond mechanical resonators.
Engineering Support
Section titled âEngineering SupportâThe transition from 5.1 ”s TRabi to 2.9 ms TRabi confirms the promise of hybrid photon-phonon quantum control. 6CCVDâs in-house PhD team provides expert consultation on material selection for similar NV-based Quantum Information Processing and Sensing projects, specifically assisting with:
- Choosing the optimal diamond purity (Optical Grade SCD) necessary to minimize background nitrogen and achieve relaxation-limited coherence.
- Defining specific SCD thickness and surface finishes optimized for high-Q mechanical resonator etching and bonding.
- Implementing necessary post-processing steps, such as high-temperature annealing requirements post-implantation.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We study the parametric interaction between a single Nitrogen-Vacancy\nelectronic spin and a diamond mechanical resonator in which the spin is\nembedded. Coupling between spin and oscillator is achieved by crystal strain,\nwhich is generated upon actuation of the oscillator and which parametrically\nmodulates the spinsâ energy splitting. Under coherent microwave driving of the\nspin, this parametric drive leads to a locking of the spin Rabi frequency to\nthe oscillator mode in the megahertz range. Both the Rabi oscillation decay\ntime and the inhomogeneous spin dephasing time increase by two orders of\nmagnitude under this spin-locking condition. We present routes to prolong the\ndephasing times even further, potentially to the relaxation time limit. The\nremarkable coherence protection that our hybrid spin-oscillator system offers\nis reminiscent of recently proposed concatenated continuous dynamical\ndecoupling schemes and results from our robust, drift-free strain-coupling\nmechanism and the narrow linewidth of the high-quality diamond mechanical\noscillator employed. Our findings suggest feasible applications in quantum\ninformation processing and sensing.\n