Laser micromachining of diamond - A viable photonic and optofluidic platform
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-01-01 |
| Journal | EPJ Web of Conferences |
| Authors | Ottavia Jedrkiewicz, Akhil Kuriakose, Argyri N. Giakoumaki, Giulio Coccia, Monica Bollani |
| Institutions | University of Insubria, Istituto di Fotonica e Nanotecnologie |
| Citations | 1 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Integrated Diamond Photonic and Optofluidic Platforms
Section titled âTechnical Documentation & Analysis: Integrated Diamond Photonic and Optofluidic PlatformsâExecutive Summary
Section titled âExecutive SummaryâThis documentation analyzes the successful application of ultrafast laser micromachining (fs/ps pulses) to create integrated quantum photonic and optofluidic devices on CVD diamond.
- Integrated Platform: Demonstration of a viable lab-on-chip prototype combining optical, electrical, and microfluidic components on a single diamond substrate.
- Core Components: Successful fabrication of essential building blocks, including optical waveguides, deterministically placed Nitrogen Vacancy (NV) centers, graphitic conductive wires, microchannels, and through-holes.
- Material Requirement: The research utilized a 500 ”m-thick CVD diamond sample, requiring high optical quality and purity suitable for NV center formation.
- Advanced Machining: Utilization of non-diffracting Bessel beams, alongside standard Gaussian beams, to achieve high-aspect ratio microstructures and single-pass deep ablation.
- Photonic Performance: Waveguides achieved 6 dB insertion loss and a 10 ”m Mode Field Diameter (MFD) at 635 nm, demonstrating effective light guidance.
- Quantum Sensing Potential: The integration of ensemble NV centers within waveguides enhances light-matter interaction, paving the way for compact, quantum-based electric and magnetic field sensors.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research detailing the performance and dimensions of the fabricated components.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Substrate Thickness | 500 | ”m | CVD Diamond sample used for graphitic wires |
| Waveguide Length | 5 | mm | Total length of the inscribed optical path |
| Waveguide Depth | 50 | ”m | Position below the diamond surface |
| Insertion Loss | 6 | dB | Measured performance of the 5 mm waveguide |
| Mode Field Diameter (MFD) | 10 | ”m | Measured at 635 nm wavelength |
| Operating Wavelength | 635 | nm | Visible light (red) |
| Laser Pulse Energy Range | 2 to 11 | ”J | Used for graphitic wire generation |
| Microchannel Geometry (Bessel) | V-shaped | N/A | High-aspect ratio trenches achieved via single pass |
| Microchannel Geometry (Gaussian) | Square-shaped | N/A | Regular channels achieved via multiple passes |
Key Methodologies
Section titled âKey MethodologiesâThe integration of photonic and microfluidic elements relied on precise control of ultrafast laser parameters and post-processing steps.
- Ultrafast Laser Micromachining: Employing femtosecond (fs) or picosecond (ps) pulses to minimize thermal effects and heat transfer during the nonlinear absorption process, crucial for transparent materials like diamond.
- Waveguide Inscription: Writing two closely spaced modification lines, which locally decrease the refractive index, creating a stressed central region capable of guiding light.
- NV Center Creation: Using specific fs laser pulse energy regimes to create vacancies via static exposure, followed by high-temperature annealing. This mobilizes vacancies to be captured by substitutional nitrogen impurities, forming NV centers.
- Graphitic Wire Generation: Tailoring laser processing parameters (pulse energy 2-11 ”J) using non-diffracting Bessel beams for bulk modification, creating conductive graphitic paths throughout the 500 ”m thick sample.
- Microchannel Fabrication: Utilizing Bessel beams for single-pass, high-aspect ratio V-shaped trenches, or standard Gaussian beams in multiple passes for regular square-shaped channels suitable for optofluidics.
- Through-Hole Drilling: Realized via a micro-drilling process combining Bessel machining with a trepanning-like technique, enabling the creation of microfluidic interfaces in thick diamond.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-purity, precision-engineered diamond substrates required to replicate and advance this research into commercial prototypes. Our MPCVD capabilities meet or exceed the material specifications necessary for integrated quantum and optofluidic platforms.
Applicable Materials
Section titled âApplicable Materialsâ| Research Requirement | 6CCVD Material Solution | Technical Advantage |
|---|---|---|
| High-Purity CVD Diamond (500 ”m thick) | Optical Grade Single Crystal Diamond (SCD) | Ultra-low intrinsic nitrogen content ensures optimal NV center formation and long spin coherence times (T2) at ambient temperature. |
| Large-Area Integration | Polycrystalline Diamond (PCD) up to 125 mm | For scaling lab-on-chip devices, 6CCVD offers PCD wafers up to 125 mm diameter, maintaining high purity and optical clarity. |
| Electrical Interfacing & Sensing | Boron-Doped Diamond (BDD) Films | For applications requiring integrated electrochemical sensing or robust electrical contacts, BDD films offer tunable conductivity and superior chemical inertness. |
Customization Potential
Section titled âCustomization PotentialâThe complexity of integrated optofluidic devices demands highly customized substrates. 6CCVD provides comprehensive services to support advanced fabrication.
- Precision Thickness Control: We supply both SCD and PCD plates with precise thickness control, ranging from 0.1 ”m up to 500 ”m (SCD) and up to 10 mm (Substrates), matching the 500 ”m requirement exactly.
- Ultra-Low Roughness Polishing: Achieving low insertion loss (6 dB) requires exceptional surface quality. 6CCVD guarantees Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD, minimizing scattering losses during laser inscription and light propagation.
- Custom Metalization Stacks: While the paper utilized graphitic wires for conductivity, 6CCVD offers in-house deposition of robust metal stacks (e.g., Ti/Pt/Au, W/Cu) for reliable electrical interfacing and bonding to microfluidic components.
- Custom Dimensions and Shaping: We provide laser cutting and shaping services to produce custom plates and wafers, facilitating the integration of complex microfluidic channels and through-holes prior to laser processing.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in material science for quantum and optical applications. We offer consultation services to optimize material selection for similar Quantum Sensing and Optofluidic projects.
- Material Selection: Guidance on choosing between SCD (for highest NV quality) and PCD (for largest area/cost efficiency) based on specific device requirements (e.g., coherence time vs. device size).
- Interface Optimization: Assistance in designing optimal metalization layers for electrical contacts and thermal management in integrated diamond devices.
- Global Logistics: We ensure reliable global shipping (DDU default, DDP available) for time-sensitive research and development projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We describe how the ultrafast laser micromachining technique applied with different writing methods can be used for the creation of various building blocks essential for the realization of a photonic and optofluidic diamond platform. Waveguides, NV centers, conductive wires, microchannels and microholes can be obtained thanks to laser microfabrication with suitable pulse parameters, making use not only of standard Gaussian laser beams but also of non-diffracting Bessel beams, the latter especially in all those cases where single pass high aspect-ratio microstructures or ablated areas are needed.