Beamtek CVD Diamond Windows

• Since 2016, Beamtek has specialized in the research and development of CVD diamond windows, with a fully in-house manufacturing process—from raw material acquisition to final production.
• We offer ultra-precision nanometer-grade surface polishing, high-temperature ultra-high vacuum diffusion bonding, and precise thermal control. Through years of technical accumulation and process optimization, we have successfully scaled up from early-stage 5 mm single-crystal diamond windows to the stable mass production of 15 mm single-crystal and 35 mm polycrystalline diamond windows. We continue to advance toward larger sizes and higher precision.
• After CVD diamond growth, the material undergoes a series of high-precision processes to meet the requirements of high-performance optical components. Due to diamond’s extreme hardness, processing can easily cause cracks, chipping, or thermal damage—each step requires precise control and specialized equipment. The process begins with laser or wire EDM cutting to segment the diamond wafer into the desired sizes while minimizing thermal stress. Multi-stage grinding with diamond tools is then used to control thickness and shape the edges to the required profile (e.g., circular or square). To improve optical transmission and surface quality, the windows undergo nanometer-level precision polishing, achieving surface roughness as low as Ra 10 nm or better. Finally, the diamond window is bonded to copper or stainless-steel mounts using high-temperature ultra-high vacuum diffusion bonding, ensuring airtightness and mechanical stability for high-vacuum applications.

• CVD diamond is a synthetic diamond material produced using Chemical Vapor Deposition. It offers exceptional thermal conductivity, hardness, chemical resistance, and broadband optical transparency, making it ideal for high-performance optical windows, especially in demanding environments.
• CVD diamond windows possess outstanding physical and optical properties, making them suitable for a wide range of demanding environments. They feature exceptional hardness and wear resistance, making them scratch- and impact-resistant. They also offer excellent transparency and low absorption across a broad spectrum, from ultraviolet to far-infrared. With extremely high thermal conductivity, they efficiently dissipate heat, making them ideal for use in high-power laser systems. Additionally, CVD diamond is highly resistant to chemical corrosion and radiation, has a low thermal expansion coefficient, and maintains excellent dimensional stability. These properties make it widely used in fields such as lasers, infrared optics, aerospace, defense, semiconductors, and medical technology, making it an ideal choice for high-performance optical windows.
• Windows intended for optical applications are polished to achieve exceptionally smooth surfaces. The standard surface roughness is typically less than 10 nm RMS.
• Beamtek offer customized Single-crystal and polycrystalline CVD diamond windows.

CVD Diamond Windows

CVD diamond is a synthetic diamond material produced using Chemical Vapor Deposition. It offers exceptional thermal conductivity, hardness, chemical resistance, and broadband optical transparency, making it ideal for high-performance optical windows, especially in demanding environments.

CVD diamond windows are available in two main forms:

Single Crystal CVD Diamond Windows

✅ Definition:

Produced using homoepitaxial growth on a single diamond seed substrate, forming a continuous and defect-free diamond lattice.

Key Properties:

• Exceptional optical clarity in infrared (IR), visible, and even ultraviolet (UV) regions.
• No grain boundaries, which reduces scattering and absorption.
• Ultra-high thermal conductivity (up to 2000 W/m·K).
• Extremely hard and chemically inert.
• High laser damage threshold, suitable for high-power laser applications.

Typical Specifications:

• Thickness: Typically 0.3–1.5 mm
• Transmission: >70% in 2–5 µm range; varies by wavelength and coating
• Surface roughness: <5 nm RMS (polished)

Applications:

• High-power CO₂ and solid-state laser output windows
• Optical windows in aerospace and defense
• High-pressure/high-temperature viewports
• Spectroscopy windows in harsh or corrosive environments

Polycrystalline CVD Diamond Windows

✅ Definition:

Grown on non-diamond substrates, forming a structure made of many small diamond grains (crystallites) fused together.

Key Properties:

• Broad IR transparency (especially mid-IR to far-IR: ~2 to 20+ µm).
• Visible transparency is limited due to light scattering at grain boundaries.
• High mechanical strength and thermal shock resistance.
• More affordable and scalable than single crystal diamond.
• Slight surface haze or texture due to polycrystalline nature.

Typical Specifications:

• Thickness: Can be thicker (1–3 mm or more)
• Transmission: ~55–65% in 8–12 µm range (uncoated), improves with AR coatings
• Surface roughness: 10–30 nm RMS (standard polished)

Applications:

• IR windows for industrial and military optics
• Protective windows in harsh environments (e.g., sensors, process monitoring)
• Laser beam delivery systems (lower power than single crystal use)
• Vacuum and high-temperature chamber windows 

Comparison Summary