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Polycrystalline optical Cvd Diamond Wafer Polycrystalline cvd diamond film for X-ray Optics 10*0.3
Polycrystalline Optical CVD Diamond
Polycrystalline chemical vapor deposition (CVD) diamond is a synthetic diamond material produced by depositing carbon atoms from a gas phase onto a substrate under controlled conditions. Unlike single-crystal diamond, it consists of multiple diamond crystallites with varying orientations, resulting in a polycrystalline structure. This material combines the exceptional optical, thermal, and mechanical properties of diamond with the scalability and versatility of CVD technology, making it a valuable solution for demanding optical applications.
Key Properties
Broadband Transparency: CVD diamond exhibits high transmittance across a wide spectral range, from ultraviolet (UV) to far-infrared (IR), including the visible and mid-IR regions.
High Thermal Conductivity: With the highest known thermal conductivity (~2000 W/m·K), it effectively manages heat in high-power optical systems.
Exceptional Hardness and Durability: It is extremely resistant to abrasion, corrosion, and radiation, ensuring longevity in harsh environments.
Low Thermal Expansion: Its low coefficient of thermal expansion minimizes shape distortion under thermal stress.
High Laser Damage Threshold: Ideal for high-power laser optics, such as windows and lenses.
Manufacturing Process
Polycrystalline CVD diamond is typically grown using microwave plasma-assisted CVD (MPCVD) or hot filament CVD (HFCVD). A carbon-rich gas mixture (e.g., methane and hydrogen) is activated to form a plasma, depositing carbon atoms as diamond on a substrate (e.g., silicon or refractory metals). The polycrystalline structure forms due to nucleation on non-diamond substrates, with grain size increasing with thickness. Post-growth processing, including laser cutting, polishing, and annealing, is employed to achieve the desired optical surface quality and dimensions.
Applications
High-Power Laser Optics: Windows, lenses, and beam combiners for CO₂, fiber, and excimer lasers.
Infrared Optics: Windows and domes for IR imaging and sensing in aerospace and defense.
Synchrotron and X-ray Optics: Beamline components and windows due to high radiation hardness.
Thermal Management: Heat spreaders and sinks for high-power optical devices.
Scientific and Industrial Sensors: Optics for spectroscopy and harsh environment sensing.
Advantages:
Superior optical performance across wavelengths.
Outstanding durability and thermal properties.
Scalable to larger sizes and complex shapes compared to single-crystal diamond.
Limitations:
Light scattering at grain boundaries can reduce transmittance, especially in the UV and visible ranges.
Surface roughness may require advanced polishing for high-precision optics.
Generally higher cost than conventional optical materials like glass or sapphire.
Polycrystalline CVD diamond
polycrystalline CVD (chemical vapour deposition) synthetic diamond products are manufactured by a chemical vapour deposition (CVD) process and are subject to tightly controlled growth conditions during manufacturing and equally stringent quality control procedures.
