Beam Loss Monitors for Energy Measurements in Diamond Light Source
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2018-01-01 |
| Authors | Niki Vitoratou, P. Karataev, Guenther Rehm |
| Analysis | Full AI Review Included |
Technical Analysis and Commercial Solutions for NV Center Diamond
Section titled âTechnical Analysis and Commercial Solutions for NV Center DiamondâBased on: On investigation of optical and spin properties of NV centers in aggregates of detonation nanodiamonds (AIP Conf. Proc. 1936, 020001 (2018))
Section titled âBased on: On investigation of optical and spin properties of NV centers in aggregates of detonation nanodiamonds (AIP Conf. Proc. 1936, 020001 (2018))âExecutive Summary
Section titled âExecutive SummaryâThis research investigates the optical and electronic spin properties of Nitrogen-Vacancy (NV) centers in aggregates of inexpensive Detonation Nanodiamonds (DND), proving their viability as cost-effective quantum emitters and biosensors.
- Cost-Effective Performance: DND aggregates, which are significantly cheaper and easier to produce than single-crystal nanodiamonds (NDs), demonstrate spin properties (coherence time Tâ) comparable to, or even better than, conventional 50 nm single-crystal NDs.
- Enhanced Brightness: The porous aggregate structure leads to a reduced internal reflection effect, resulting in NV centers that are approximately 2.2 times brighter (2.4 x 10â” counts/second) compared to isolated 50 nm crystalline nanodiamonds (1.1 x 10â” counts/second).
- Spin Coherence: The NV centers in DND aggregates achieve a spin coherence time (Tâ) ranging from 3 ”s to 5 ”s via Hahn echo sequencing, matching typical values for moderate-sized NDs (50-100 nm).
- Quantum Identification: NV centers were confirmed using Optically Detected Magnetic Resonance (ODMR), showing a sharp zero-field splitting line near 2.87 GHz.
- Manipulation Capability: Coherent manipulation of the electron spin was demonstrated via Rabi oscillations, achieving a frequency of 10.4 MHz (96 ns 2Ï pulse).
- Primary Application Targets: The findings position DND aggregates as strong candidates for high-brightness, cheap sources of single-photon radiation for quantum information processing, biosensing, and biocompatible bioimaging.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Nanocrystal Size (DND) | 2 - 5 | nm | Measured by TEM; Mean size 3.3 nm. |
| Aggregate Size Range | Tens to 100 | nm | Porous compound structure. |
| Average Saturated Brightness (DND Aggregates) | 2.4 ± 0.7 x 10┠| counts/second | Measured maximum fluorescence count rate. |
| Brightness Ratio (Aggregates / 50 nm ND) | 2.2 | X | Aggregates are 2.2 times brighter than 50 nm crystalline nanodiamonds. |
| NV Zero-Field Splitting | Near 2.87 | GHz | Measured via ODMR in the absence of external magnetic field. |
| Applied Magnetic Field (B) | ~20 | G | Used to separate the ms = ±1 magnetic sublevels. |
| Rabi Oscillation Frequency | 10.4 | MHz | Coherent manipulation frequency under MW excitation. |
| 2Ï Pulse Duration | 96 | ns | Time required for a 2Ï rotation of the spin state. |
| Coherence Time (Tâ) | 3 - 5 | ”s | Extended using Hahn echo sequence. Typical for 50-100 nm NDs. |
| Single Photon Statistics Threshold | gÂČ(0) < 0.5 | Dimensionless | Statistical antibunching achieved, indicating single photon dominated statistics. |
Key Methodologies
Section titled âKey MethodologiesâThe investigation relied on a combination of materials preparation, high-resolution imaging, and advanced quantum spectroscopic techniques to characterize the NV centers:
- Material Preparation and Sizing: Detonation nanodiamond solutions were processed to select large aggregates formed easily in water. Particle size distribution was analyzed using Transmission Electron Microscopy (TEM), confirming DND sizes between 2 nm and 5 nm.
- Confocal Setup & MW Integration: Optical and electronic spin properties were measured using a custom-built confocal setup equipped with a microwave (MW) part, allowing for manipulation of the NV center electron spin.
- ODMR Measurement: Optically Detected Magnetic Resonance (ODMR) was employed, using a permanent magnet (~20 G) to separate the ms = ±1 sublevels, allowing for immediate identification of the NV center via the sharp line near 2.87 GHz.
- Coherent Spin Control (Rabi Oscillations): Coherent manipulation of the electron spin was achieved by varying MW pulse duration and measuring the spin contrast (C) to determine the Rabi oscillation frequency (10.4 MHz).
- Coherence Time Extension (Hahn Echo): The Hahn echo sequence (Ï/2 - Ï/2 - Ï - Ï/2 - Ï/2) was implemented to mitigate environmental noise and extend the spin coherence time (Tâ) from Tâ* (0.9-1.3 ”s) to Tâ (3-5 ”s).
- Photon Statistics Verification: The second-order correlation function gÂČ(0) was measured. Aggregates demonstrating a statistical antibunching threshold of gÂČ(0) < 0.5 were selected, confirming single-photon-dominated emission.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research demonstrates that high-quality NV center performance can be achieved even with aggregated DND. However, the paper notes that the highest quality NV centers (Tâ exceeding 3-5 ”s) are typically realized in isotopically pure, low-strain diamondâa core specialization of 6CCVDâs MPCVD manufacturing.
Replication and advancement of this quantum research necessitate highly controlled precursor materials, which 6CCVD provides as an expert supplier of CVD diamond wafers and custom processing.
Applicable Materials
Section titled âApplicable MaterialsâFor researchers aiming to achieve quantum coherence times superior to those demonstrated in DND aggregates, or requiring large-scale integration of NV centers, 6CCVD recommends:
| Material Grade | Application Focus | 6CCVD Capability |
|---|---|---|
| Optical Grade SCD (High Purity) | Achieving maximum coherence time (Tâ). | Ultra-low nitrogen content (ppm to ppb level) and minimal lattice defects, essential for creating long-lived quantum coherence in NV centers. Ideal for implantation and annealing processes that yield the industry-leading Tâ values. |
| PCD/Substrate Plates | Large-area bio-sensor arrays and heat dissipation. | Wafers up to 125mm size, allowing for massive parallelization of NV-based sensors or integration into high-power microwave circuitry for ODMR. |
| Custom BDD (Boron-Doped) | Integrated NV/Quantum Device Substrates. | Can serve as electrically conductive platforms for microwave transmission lines used in ODMR experiments, enhancing MW field uniformity and coupling efficiency. |
Customization Potential
Section titled âCustomization PotentialâThe integration of quantum emitters like NV centers into functional devices requires precise control over geometry and surface interfacing. 6CCVD offers specialized engineering services to accelerate development:
- Custom Dimensions and Thickness: We supply SCD and PCD substrates in thicknesses from 0.1 ”m up to 500 ”m, and bulk substrates up to 10 mm. This allows for optimization for either thin-film sensing or robust bulk devices. Custom laser cutting ensures wafers are provided in the exact geometric dimensions required for confocal or microwave setups.
- Advanced Polishing: Surface roughness is critical for reducing spin relaxation caused by surface defects. Our in-house polishing capability guarantees ultra-smooth surfaces: Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD.
- Multi-Layer Metalization: The ODMR technique relies heavily on robust microwave delivery. 6CCVD provides custom metal deposition services, including Au, Pt, Pd, Ti, W, and Cu, crucial for fabricating coplanar waveguides (CPWs) directly onto the diamond substrate, maximizing MW coupling efficiency for Rabi oscillations and Tâ measurements.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD material science team specializes in controlling the CVD growth environment to produce quantum-grade diamond. Our experts can assist in material selection and optimization for specific quantum sensing and bioimaging projects:
- Nitrogen Doping Control: Tailoring the initial nitrogen concentration in SCD or PCD to optimize the resulting NV center density during subsequent irradiation and annealing steps.
- Strain Engineering: Providing low-strain materials that minimize inhomogeneous broadening, which is crucial for achieving high Rabi oscillation fidelity and maximizing Tâ.
- Surface Chemistry and Integration: Consultation on optimal surface preparation and metalization schemes for robust integration into magnetometry and biosensing platforms.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We ship globally, with DDU default and DDP options available.
View Original Abstract
Resonant Spin Depolarization is a high precision technique for beam energy measurement employed in the Diamond Light Source storage ring. The relation between spin tune and beam energy can be used to determine the energy of a transversely polarized beam. Vertical oscillations excite the beam at frequencies that match the fractional part of the spin tune and the beam loss rate is used to monitor the beam depolarization. However, the standard procedure of these measurements is intrusive and not compatible with user operation of a light source. The Advanced Resonant Spin Depolarization (AdReSD) project aims to extend and improve the method with the goal of making the measurements compatible with the user operation, for instance by acting only on a small fraction of the stored beam. As a first step, we are investigating the beam loss monitors that will be used to detect beam depolarization. The material, location and optimal geometry of the detector to capture the largest fraction of the radiation footprint resulting from beam losses are studied. Results and designs are presented and future work is discussed.