A quantum radio frequency signal analyzer based on nitrogen vacancy centers in diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-07-27 |
| Journal | Communications Engineering |
| Authors | Simone Magaletti, Ludovic Mayer, Jean-François Roch, Thierry Debuisschert |
| Institutions | Thales (France), Laboratoire Lumière, Matière et Interfaces |
| Citations | 31 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThe Quantum Diamond Signal Analyzer (Q-DiSA) leverages the spin properties of Nitrogen-Vacancy (NV) centers in diamond to achieve real-time, broadband Radio Frequency (RF) spectral analysis at room temperature.
- Core Value Proposition: Provides a compact, low-power alternative to traditional Fast Fourier Transform (FFT) electronic spectrum analyzers, overcoming the bandwidth limitations imposed by Analog-to-Digital Converters (ADCs).
- Broadband Performance: Demonstrates real-time spectral analysis over a large tunable frequency range of 25 GHz (10 MHz up to 27 GHz).
- High Resolution: Achieves frequency resolution down to 1 MHz and instantaneous bandwidth up to 4 GHz, enabled by the controlled magnetic field gradient.
- High Dynamic Range: Exhibits a large dynamic range of 40 dB, capable of detecting signals from 23 dBm down to -17 dBm.
- Real-Time Operation: Utilizes a continuous wave (CW) wide-field imaging mode, allowing simultaneous detection of all frequencies within the bandwidth with 100% Probability of Intercept (POI).
- Architecture Innovation: Achieves high Zeeman shift and preserves NV spin properties by combining a specific {100} CVD diamond cut (with {110} lateral facets) with a simplified spherical magnet arrangement, ensuring the static magnetic field remains aligned along the NV center axis during frequency tuning.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Tunable Frequency Range | 10 MHz to 25 | GHz | Demonstrated range (up to 27 GHz achieved) |
| Instantaneous Bandwidth (Max) | Up to 4 | GHz | Achieved at 22 GHz center frequency |
| Frequency Resolution (Best) | Down to 1 | MHz | Achieved at low frequencies (2.6 GHz) |
| Temporal Resolution (Best) | 2 | ms | Achieved at 1.8 GHz (C=6%, SNR=5) |
| Dynamic Range | 40 | dB | Detection range: 23 dBm to -17 dBm |
| Ground State ZFS (D) | 2.87 | GHz | Zero-Field Splitting |
| Gyromagnetic Ratio (Îł) | 28 | GHz T-1 | NV center gyromagnetic ratio |
| Static Magnetic Field (B) (Max) | ~1 | T | Produced by Neodymium spherical magnet |
| Diamond Type | {100} CVD | Single-crystal | Optical grade, few ppb NV concentration |
| Diamond Dimensions | 4.5 x 4.5 x 0.5 | mm | Plate size |
| Laser Wavelength | 532 | nm | CW excitation |
| Laser Power (P) | 300 | mW | Used for measurements |
| Laser Saturation Parameter (s) | 0.15 | N/A | Calculated saturation parameter |
| Intrinsic Linewidth | ~500 | kHz | Attributed to spin decoherence (13C nuclear spin bath) |
| Spatial Resolution | 0.66 x 0.66 | Âľm2 | Defines frequency resolution |
Key Methodologies
Section titled âKey Methodologiesâ- Diamond Selection and Mounting: A commercial {100} single-crystal CVD diamond plate (Element Six) doped with NV centers (few ppb) was used. The plate was mounted with a {110} facet parallel to the horizontal plane to align one NV family axis with the magnetic field reference axis.
- Magnetic Field Generation and Alignment: A 1.3 cm spherical Neodymium magnet was used to generate the strong static magnetic field (up to 1 T) and the necessary gradient. The magnet was mounted on a three-axis translation stage to precisely adjust the magnet-diamond distance, thereby tuning the central resonance frequency.
- NV Axis Preservation: The specific diamond cut and magnet arrangement ensured that the static magnetic field remained aligned along the chosen NV center axis, preserving the spin-dependent optical properties necessary for large frequency tuning.
- Optical Excitation and Collection: NV centers were excited using a CW 532 nm laser focused to a 38 Âľm waist through a {110} facet. Photoluminescence (PL) was collected through the top {110} facet using a 20x objective (0.33 NA) and filtered (697/75 nm band-pass filter).
- RF Signal Application: The microwave signal was introduced via a 1 mm diameter loop antenna placed near the diamond, generating a homogeneous RF magnetic field perpendicular to the NV center axis.
- Q-DiSA Spectral Encoding: The static magnetic field gradient spatially encodes the NV center resonance frequencies. NV centers at different positions (pixels) resonate at different MW frequencies, allowing the camera to capture the entire spectral content simultaneously.
- Calibration and Processing: An ODMR calibration procedure maps each frequency to a specific set of pixels (iso-B lines). Spectral retrieval involves summing the PL signal over all pixels corresponding to the resonant frequency, which significantly improves the Signal-to-Noise Ratio (SNR) by leveraging the wide-field imaging mode.
Commercial Applications
Section titled âCommercial ApplicationsâThe Q-DiSA technology is suitable for applications requiring real-time, broadband spectral monitoring in compact, room-temperature environments.
- Defense and Aerospace:
- Radar systems and electronic warfare (EW).
- Real-time monitoring of complex electromagnetic landscapes.
- High Probability of Intercept (POI) detection for transient signals.
- Telecommunications:
- Cognitive Radio Networks (CRN) requiring instantaneous spectral awareness.
- Electromagnetic Compatibility (EMC) analysis over broad frequency bands (tens of GHz).
- Quantum Sensing and Metrology:
- Compact, room-temperature magnetometers and electrometers.
- Integration into on-board devices where low power consumption and compact design are critical.
- Scientific Instrumentation:
- Broadband spectral analysis tools complementary to cryogenic techniques (e.g., spectral hole burning).