Thermometry of an optically levitated nanodiamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-07-01 |
| Journal | AVS Quantum Science |
| Authors | François RiviÚre, Timothée de Guillebon, Léo Maumet, G. Hétet, Martin Schmidt |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Thermometry of Optically Levitated Nanodiamonds
Section titled âTechnical Documentation & Analysis: Thermometry of Optically Levitated NanodiamondsâExecutive Summary
Section titled âExecutive SummaryâThis research utilizes NV center spin resonance to characterize the thermal properties and absorption mechanisms of levitated nanodiamonds, identifying critical material limitations for quantum spin-levitation experiments.
- Sensitive Thermometry: The temperature dependence of the NV center zero-field splitting, D(T), was successfully calibrated and used as a highly sensitive internal thermometer for single levitated nanodiamonds, achieving a resolution of approximately 1 K.
- Extrinsic Absorption Dominance: Significant heating was observed due to absorption of the infrared trapping laser ($\lambda = 1550$ nm). The measured absorption cross-section ($\sigma_{abs}$) is orders of magnitude higher than expected for pure diamond.
- Volume-Dependent Heating: Analysis of 46 nanodiamonds confirmed that absorption is extrinsic (due to defects/impurities) and volume-dominated, scaling proportionally to the cube of the hydrodynamic radius ($\sigma_{abs} \propto r_{hydro} ^{3}$).
- Material Limitation Identified: The heavily doped (HPHT) nanodiamonds used, rich in nitrogen ([N]~200 ppm), demonstrate that internal crystallographic defects and impurities are the primary source of heating.
- Path to Optimization: The work explicitly calls for the use of ultra-pure, CVD-grown diamond materials with controlled doping to minimize extrinsic absorption and advance quantum spin-levitation dynamics.
- 6CCVD Value Proposition: 6CCVD specializes in the high-purity MPCVD SCD and PCD required to overcome the identified thermal limitations and optimize material for next-generation quantum applications.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Trapping Laser Wavelength ($\lambda$) | 1550 | nm | High-power infrared laser (Near-Infrared, NIR) |
| NV Excitation Laser Wavelength ($\lambda$) | 532 | nm | Green laser for photoluminescence (PL) detection |
| Maximum Measured Temperature (Tmax) | 650 | K | Internal temperature before particle loss from trap |
| Temperature Resolution ($\Delta$T) | ~1 | K | Achieved sensitivity based on 1.5 s/frequency acquisition time |
| Zero Field Splitting Shift (dD/dT) | -74 | kHz/K | Temperature derivative near ambient temperature |
| Operating Gas Pressure Range (pgas) | 15 to 45 | mbar | Stability region for levitation experiments |
| Nitrogen Impurity Concentration ([N]) | ~200 | ppm | Concentration in FND-br100 nanodiamonds used |
| NV Center Concentration ([NV]) | ~2 | ppm | Concentration in FND-br100 nanodiamonds used |
| Absorption Cross-Section Scaling | $\sigma_{abs} \propto r_{hydro} ^{3}$ | N/A | Confirms volume-dominated absorption mechanism |
| Estimated Bulk Absorption Coefficient ($\alpha_{bulk}$) | 4 to 662 | cm-1 | Derived from $\sigma_{abs}$ measurements at 1550 nm |
| Diamond Relative Dielectric Constant (Real Part, $\epsilonâ$) | 5.7 | N/A | Used for calculating imaginary part ($\epsilonâ$) |
Key Methodologies
Section titled âKey MethodologiesâThe experiment involved two main stages: calibration of the NV thermometer and measurement of the levitated particle heating.
-
NV Thermometry Calibration (On-Substrate):
- Nanodiamonds (FND-br100) were spin-coated onto a quartz coverslip.
- A Pt100 thermal sensor and PID device controlled heating from ambient temperature up to 411 K.
- Electron Spin Resonance (ESR) was measured using 532 nm green laser excitation and microwave signals delivered via a copper wire.
- The zero-field splitting parameter D was fitted using a bi-Lorentzian function, and its temperature dependence D(T) was calibrated against the known polynomial equation (Toyli et al.).
-
Optical Levitation and Heating Measurement:
- A single nanodiamond was trapped at the focus of a high-NA objective using a high-power infrared laser ($\lambda = 1550$ nm).
- The system was enclosed in a vacuum chamber, with residual gas pressure ($p_{gas}$) controlled between 15 and 45 mbar.
- The internal temperature ($T_{int}$) was determined by measuring the D parameter shift via ESR as a function of the trapping laser power density ($I_{las}$) and $p_{gas}$.
- $T_{int}$ was modeled based on thermal equilibrium between absorbed power ($P_{abs}$) and gas conduction ($P_{cond}$).
-
Absorption Cross-Section Determination:
- The hydrodynamic radius ($r_{hydro}$) of 46 individual nanodiamonds was determined from the particle dynamics damping coefficient ($\Gamma$) in the rarefied gas regime.
- The heating coefficient ($\beta_{heat}$) was calculated from the linear fit of $T_{int}$ vs. $I_{las}/p_{gas}$.
- The absorption cross-section ($\sigma_{abs}$) was derived from $\beta_{heat}$ and $r_{hydro}$, confirming a volume-dependent scaling ($\sigma_{abs} \propto r_{hydro} ^{3}$).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research highlights that the current limitation in quantum spin-levitation experiments is the extrinsic absorption of the diamond material, necessitating a shift toward ultra-pure, CVD-grown diamond with precise defect control. 6CCVDâs expertise in MPCVD diamond is uniquely positioned to supply the materials required to replicate and extend this critical research.
| Applicable Materials & Services | Research Requirement Addressed | 6CCVD Technical Specification |
|---|---|---|
| Optical Grade Single Crystal Diamond (SCD) | Need for Ultra-Pure Material: Minimizing extrinsic absorption ($\alpha_{bulk}$) at 1550 nm. | SCD grown via MPCVD ensures the highest purity, extremely low nitrogen content (sub-ppb available), and minimal crystallographic defects, drastically reducing volume-dominated heating. |
| Custom Doping and Defect Engineering | Need for Controlled Doping: Creating single NV centers in ultra-pure material for optimized quantum experiments. | Precision control over nitrogen incorporation during growth allows for tailored NV density. We can supply SCD or PCD with specific defect concentrations (e.g., low-density NV or SiV centers). |
| Custom Diamond Substrates for Nanofabrication | Need to Test CVD-Grown Nanodiamonds: Providing high-quality source material for subsequent milling/etching. | SCD and PCD plates available in thicknesses from 0.1 ”m to 500 ”m. Custom dimensions up to 125mm (PCD) are standard. |
| Advanced Polishing Services | Surface Quality Impact: While volume effects dominate, surface quality remains important for levitation stability. | SCD polishing achieves Ra < 1 nm. Inch-size PCD polishing achieves Ra < 5 nm, providing superior surface quality for particle generation. |
| Custom Metalization Services | Future Integration: Potential need for on-chip microwave delivery or thermal management layers. | Internal capability for depositing Au, Pt, Pd, Ti, W, and Cu layers, enabling integrated quantum device fabrication. |
| Global Logistics Support | International Research Collaboration: Ensuring timely delivery of sensitive materials. | Global shipping is available (DDU default, DDP available) to support research institutions worldwide. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists specializes in optimizing diamond properties for quantum applications, including spin-mechanics and sensing. We offer consultation on material selection, growth parameters, and post-processing techniques (e.g., annealing for NV creation) to ensure the supplied diamond meets the stringent purity and defect control requirements necessary to overcome the thermal limitations identified in this study.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Using the spin properties of nitrogen-vacancy (NV) centers in levitated diamonds, we characterize the absorption of single nanodiamonds. We first calibrate the thermometry response of the NV centers embedded in our nanodiamonds. Then, using this calibration, we estimate the absorption cross-section of single levitated nanodiamonds. We show that this absorption is extrinsic and dominated by volumic effects. Our work opens the way to diamond material optimization for levitation quantum experiments. It also demonstrates optical levitation as a unique platform to characterize material thermal properties at the nanoparticle level.