Terahertz emission from diamond nitrogen-vacancy centers
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-05-29 |
| Journal | Science Advances |
| Authors | SĂĄndor Kollarics, Bence G. MĂĄrkus, Robin Kucsera, GergĆ Thiering, ĂdĂĄm Gali |
| Institutions | Institute for Solid State Physics and Optics, Montavid Thermodynamic Research Group |
| Citations | 10 |
| Analysis | Full AI Review Included |
Terahertz Emission from Diamond Nitrogen-Vacancy Centers: A 6CCVD Technical Analysis
Section titled âTerahertz Emission from Diamond Nitrogen-Vacancy Centers: A 6CCVD Technical AnalysisâThis document analyzes the research demonstrating coherent terahertz (THz) emission from Nitrogen-Vacancy (NV) centers in single crystal diamond (SCD). The findings validate the use of diamond NV centers as a highly promising platform for next-generation tunable coherent THz sources (TASERs). 6CCVD specializes in providing the high-purity, custom-engineered MPCVD diamond materials necessary to replicate and advance this critical quantum technology research.
Executive Summary
Section titled âExecutive Summaryâ- Core Achievement: Coherent THz radiation (0.42 THz) was successfully generated from negatively charged Nitrogen-Vacancy (NV-) centers embedded in a single crystal diamond plate.
- Mechanism: Population inversion was achieved through selective optical pumping (532 nm laser) combined with Zeeman splitting of the S=1 ground state triplet under extreme magnetic fields (up to 15 T).
- Tunability: The emitted THz frequency is tunable by adjusting the external magnetic field, offering a key advantage for broadband communication and sensing applications.
- High-Field Stability: Spin-lattice relaxation time (T1) measurements confirmed that the long relaxation time (~4 ms at room temperature) is unaffected by high magnetic fields (up to 15 T), ensuring efficient maintenance of the population inversion.
- Methodology: The study utilized highly sensitive, phase-coherent detection via High-Field/High-Frequency Electron Spin Resonance (HFESR) and Light-Induced ESR (LESR) techniques.
- Future Potential: These findings establish the diamond NV center system as a leading candidate for developing solid-state, optically pumped, coherent THz sources (TASERs) and amplifiers.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Coherent THz Emission Frequency | 0.42 (and 0.21) | THz | Corresponds to Zeeman splitting at 15 T |
| Maximum Applied Magnetic Field (B) | 15 | T | Required to achieve 0.42 THz splitting |
| Optical Pumping Wavelength | 532 | nm | CW laser used for selective Sz = 0 population |
| Laser Intensity (Incident) | 1 | W/cm2 | Power density used for illumination |
| Zero-Field Splitting (D/h) | 2.87 | GHz | NV center ground state triplet (S=1) |
| Spin-Lattice Relaxation Time (T1) | ~4 | ms | Measured at room temperature (0.33 T to 15 T) |
| Sample NV Concentration | 12 | ppm | High concentration Type 1b SCD |
| Sample Dimensions | ~5 | mm | Hexagonally cut single crystal plate |
| Polishing Requirement (Implied) | Ra < 5 | nm | Necessary for minimizing optical loss (532 nm) |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on specialized material preparation and advanced high-frequency magnetic resonance techniques:
- Material Preparation:
- Used Type 1b single crystal diamond (HPHT grown) with a high NV center concentration (12 ppm).
- NV centers were created via electron beam irradiation followed by subsequent high-temperature thermal annealing.
- High-Field Environment:
- The sample was housed in a liquid helium variable temperature insert (VTI) within a superconducting solenoid capable of generating fields up to 16 T.
- Optical Pumping:
- A frequency-doubled Nd:YAG laser (λ = 532 nm, 100 mW max) was used for continuous-wave optical excitation.
- Light was guided via a precise optics breadboard and a corrugated waveguide, passing through thin Mylar windows to minimize THz and visible light loss.
- High-Frequency ESR (HFESR) Spectroscopy:
- Spectrometer operated in the 0.052 to 0.420 THz range using phase-locked loop stabilized, frequency-multiplied microwave sources.
- Detection and Measurement:
- Detection utilized a liquid helium-cooled InSb hot-electron bolometer in a homodyne single-ended mixer configuration for phase-sensitive detection of reflected radiation.
- The Light-Induced ESR (LESR) technique, employing a double lock-in amplifier setup (modulating magnetic field at 20 kHz and laser light at 20 Hz), was critical for measuring the spin-lattice relaxation time (T1).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical need for high-quality, custom-engineered diamond substrates to advance quantum technologies. 6CCVDâs MPCVD capabilities are perfectly suited to meet and exceed the material requirements for developing diamond-based THz sources (TASERs) and amplifiers.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, 6CCVD recommends the following materials:
- Optical Grade Single Crystal Diamond (SCD): Required for high-fidelity quantum experiments. Our SCD material offers superior purity and low strain, crucial for achieving long spin coherence times (T2*) necessary for TASER operation.
- Custom Nitrogen Doped SCD: We offer precise control over nitrogen incorporation during MPCVD growth, allowing researchers to tailor the NV precursor concentration (e.g., 12 ppm equivalent) to maximize NV- yield after post-processing.
Customization Potential
Section titled âCustomization PotentialâThe development of practical THz devices requires integration of the diamond material into complex waveguide and magnetic field setups. 6CCVD provides comprehensive customization services:
| Research Requirement | 6CCVD Customization Service | Benefit to Researcher |
|---|---|---|
| Unique Plate Dimensions | Custom Dimensions & Laser Cutting | We provide SCD plates/wafers up to 500 ”m thick, and PCD wafers up to 125 mm in diameter. Precise laser cutting ensures custom geometries (e.g., 5 mm hexagonal plates) required for high-field VTI integration. |
| High Optical Coupling | Ultra-Precision Polishing (Ra < 1 nm) | Our SCD polishing achieves surface roughness Ra < 1 nm, significantly reducing the optical scattering losses (532 nm) noted in the paper, thereby maximizing pumping efficiency. |
| Device Integration (TASER/Amplifier) | Custom Metalization Services | We offer in-house deposition of standard metals (Au, Pt, Pd, Ti, W, Cu) for creating microwave/THz circuitry (e.g., coplanar waveguides) directly on the diamond surface, facilitating device fabrication. |
| Optimized NV Creation | Post-Growth Treatment Consultation | We assist in defining optimal electron beam irradiation and thermal annealing recipes to maximize the conversion efficiency to the desired NV- charge state. |
Engineering Support
Section titled âEngineering Supportâ6CCVD is more than a supplier; we are a technical partner. Our in-house PhD team can assist with material selection and optimization for similar Coherent Terahertz Source projects. We provide consultation on:
- Optimizing nitrogen concentration for specific NV density targets.
- Selecting the appropriate SCD thickness (0.1 ”m to 500 ”m) for integration into THz waveguides and resonators.
- Designing metalization schemes for efficient coupling of THz radiation.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Coherent light sources emitting in the terahertz range are highly sought after for fundamental research and applications. Terahertz lasers rely on achieving population inversion. We demonstrate the generation of terahertz radiation using nitrogen-vacancy centers in a diamond single crystal. Population inversion is achieved through the Zeeman splitting of the S = 1 state in 15 tesla, resulting in a splitting of 0.42 terahertz, where the middle S z = 0 sublevel is selectively pumped by visible light. To detect the terahertz radiation, we use a phase-sensitive terahertz setup, optimized for electron spin resonance (ESR) measurements. We determine the spin-lattice relaxation time up to 15 tesla using the light-induced ESR measurement, which shows the dominance of phonon-mediated relaxation and the high efficacy of the population inversion. The terahertz radiation is tunable by the magnetic field, thus these findings may lead to the next generation of tunable coherent terahertz sources.