Nanodiamonds enable femtosecond-processed ultrathin glass as a hybrid quantum sensor
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-04-18 |
| Journal | Scientific Reports |
| Authors | Bhavesh Kumar Dadhich, Biswajit Panda, Mehra S. Sidhu, Kamal P. Singh |
| Institutions | Indian Institute of Science Education and Research Mohali |
| Citations | 5 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Hybrid Quantum Sensors on Ultra-Thin Substrates
Section titled âTechnical Documentation & Analysis: Hybrid Quantum Sensors on Ultra-Thin SubstratesâReference: Dadhich et al., Nanodiamonds enable femtosecond-processed ultrathin glass as a hybrid quantum sensor, Scientific Reports (2023) 13:6286.
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a novel, scalable approach for fabricating multifunctional hybrid quantum sensors by combining the mechanical flexibility of ultra-thin (UT) glass with the quantum properties of Nitrogen-Vacancy (NV) centers in nanodiamonds.
- Hybrid Sensor Fabrication: Ultra-thin (30 ”m) glass cantilevers were functionalized via spin-coating of 120 nm NV nanodiamonds, followed by precise shaping using femtosecond laser ablation.
- Stable Quantum Readout: The fabricated devices exhibited stable NV quantum properties, confirmed by characteristic Zero-Phonon Lines (ZPL) at 575 nm (NVâ°) and 637 nm (NVâ»).
- Optically Detected Magnetic Resonance (ODMR): A clear ODMR signal was observed near 2.87 GHz, validating the spin initialization and readout capabilities necessary for quantum sensing.
- Multifunctional Sensing: The NV-UT cantilevers successfully demonstrated quantitative sensing of acoustic pulses, external magnetic fields (sensitivity 20 ± 2 MHz/Gauss), and local thermal shifts (sensitivity 1.3 MHz/K).
- Scalability Potential: The use of femtosecond laser processing on UT-glass suggests a viable route toward the mass production of affordable, versatile quantum devices.
- 6CCVD Value Proposition: 6CCVD offers superior Single Crystal Diamond (SCD) and Polycrystalline Diamond (PCD) substrates, enabling integrated NV centers and eliminating the mechanical and coherence limitations associated with nanodiamond films on glass.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper detailing the material properties and sensor performance:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Substrate Thickness (UT-Glass) | 30 | ”m | Commercially available Schott glass |
| UT-Glass Youngâs Modulus | 72.9 | kN/mmÂČ | Mechanical property |
| Nanodiamond Average Particle Size | 120 | nm | Used for spin-coating |
| Nanodiamond NV Concentration | 3 | ppm | Nitrogen Vacancy centers |
| Nanodiamond Coating Thickness | 1 to 2 | ”m | Continuous layer on UT-glass |
| ODMR Resonance Frequency | 2.87 | GHz | Characteristic quantum property of NVâ» |
| NVâ° Zero-Phonon Line (ZPL) | 575 | nm | Optical emission spectrum |
| NVâ» Zero-Phonon Line (ZPL) | 637 | nm | Optical emission spectrum |
| Magnetic Field Sensitivity (γ) | 20 ± 2 | MHz/Gauss | Derived from Zeeman splitting |
| Thermal Sensitivity (dv/ÎŽT) | 1.3 | MHz/K | Measured shift in ODMR resonance |
| Femtosecond Pulse Duration | 25 | fs | Laser ablation source |
| Femtosecond Laser Wavelength | 800 | nm | Central wavelength (λAIR) |
Key Methodologies
Section titled âKey MethodologiesâThe hybrid quantum sensors were fabricated and characterized using a multi-step process focusing on thin-film deposition and precision laser processing.
- Substrate Preparation: Ultra-thin (30 ”m) Schott glass sheets were cleaned using an ultrasonic bath (acetone and methanol) and dried with Nitrogen gas.
- Nanodiamond Deposition: Nanodiamond colloidal solution (120 nm size, 1 mg/mL concentration) was spin-coated onto the UT-glass at 3000 rpm for 20 s, followed by 24 hours of drying in a desiccator.
- Femtosecond Laser Ablation: A custom setup utilizing intense fs-pulses (25 fs duration, 800 nm wavelength) focused via a 10X objective (0.25 NA) was used to cut the UT-glass.
- Cantilever Shaping: The fs-beam was raster scanned (1 mm/s) in the desired pattern to fabricate mm-long cantilevers with nano-meter resolved edges and tips (a few hundred nanometers).
- Fluorescence and ODMR Setup: A custom fluorescence microscope cum ODMR setup was employed, using a 532 nm CW green laser for excitation and a Cu wire resonator (radius = 10 ”m) fed by a signal generator (1.35 to 3.1 GHz) for microwave delivery.
- Sensing Applications: External magnetic fields (up to 22.5 G) were applied via a solenoid, acoustic pulses were generated for mechanical sensing, and a 445 nm CW blue laser was used for local thermal heating measurements.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research validates the potential of integrating quantum emitters with mechanically flexible substrates. 6CCVD, as an expert MPCVD diamond supplier, offers materials and fabrication services that significantly enhance the performance, stability, and integration capabilities required to advance this technology beyond nanodiamond films on glass.
| Research Requirement/Challenge | 6CCVD Solution & Value Proposition | Applicable Materials |
|---|---|---|
| Quantum Emitter Stability & Coherence: The paper used 120 nm nanodiamond films (ensemble NV centers) which have limited spin coherence due to surface defects. | Integrated NV Centers in Bulk Diamond: 6CCVD supplies high-purity Single Crystal Diamond (SCD) wafers with in-situ grown or implanted NV centers. This provides a low-strain, stable environment, yielding significantly longer spin coherence times (T2) essential for high-fidelity quantum sensing. | Quantum Grade SCD (Controlled Nitrogen Doping) |
| Ultra-Thin Substrate Fabrication: The paper relied on 30 ”m UT-glass, which is mechanically fragile and optically lossy compared to diamond. | Precision Thinning and Polishing: We offer custom SCD and PCD plates thinned down to the required range (0.1 ”m to 500 ”m). Our SCD polishing achieves surface roughness Ra < 1 nm, providing superior optical transparency and mechanical resilience for cantilever applications. | Optical Grade SCD or Thin PCD |
| Custom Geometry & Nano-Tip Shaping: Femtosecond laser processing was used to cut the glass, a technique that can be complex for bulk diamond. | Advanced Laser Cutting and Etching: 6CCVD provides high-precision laser cutting and reactive ion etching (RIE) services to define complex geometries, such as the required cantilevers, micro-tips, and resonators, directly into the diamond substrate with high fidelity. We support plates/wafers up to 125 mm. | All SCD/PCD Materials (Custom Dimensions) |
| Integrated Microwave Delivery: The experiment used an external Cu wire resonator for ODMR. | In-House Metalization for Integrated Devices: We offer internal metalization services (Au, Pt, Pd, Ti, W, Cu) to deposit coplanar waveguides (CPWs) or microwave antennas directly onto the diamond surface, enabling highly efficient, integrated ODMR readout and eliminating external components. | SCD/PCD with Custom Metalization |
| High-Volume Production & Affordability: The paper aims for mass production of affordable sensors. | Scalable Polycrystalline Diamond (PCD): For applications where single-crystal purity is not mandatory, 6CCVD provides large-area PCD wafers (up to 125 mm) with excellent mechanical and thermal properties, ideal for high-throughput fabrication of sensor arrays. | Optical Grade PCD (Inch-size polished, Ra < 5 nm) |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD engineering team specializes in optimizing MPCVD diamond growth parameters (e.g., nitrogen concentration, thickness, and surface termination) to meet specific quantum sensing requirements. We can assist researchers in transitioning from nanodiamond films to robust, integrated bulk diamond substrates for similar hybrid nanomechanical quantum (HNQ) systems projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. Global shipping (DDU default, DDP available) ensures rapid delivery worldwide.
View Original Abstract
Abstract The quantum properties of fluorescent nanodiamonds offer great promise for fabricating quantum-enabled devices for physical applications. However, the nanodiamonds need to be suitably combined with a substrate to exploit their properties. Here, we show that ultrathin and flexible glass (thickness 30 microns) can be functionalized by nanodiamonds and nano-shaped using intense femtosecond pulses to design cantilever-based nanomechanical hybrid quantum sensors. Thus fabricated ultrathin glass cantilevers show stable optical, electronic, and magnetic properties of nitrogen-vacancy centers, including well-defined fluorescence with zero-phonon lines and optically detected magnetic resonance (ODMR) near 2.87 GHz. We demonstrate several sensing applications of the fluorescent ultrathin glass cantilever by measuring acoustic pulses, external magnetic field using Zeeman splitting of the NV centers, or CW laser-induced heating by measuring thermal shifting of ODMR lines. This work demonstrates the suitability of the femtosecond-processed fluorescent ultrathin glass as a new versatile substrate for multifunctional quantum devices.