Vacuum Viewports
Vacuum viewports are specialized windows or ports integrated into vacuum systems, allowing visual observation or the transmission of light into or out of a vacuum chamber without compromising the vacuum environment. Firebird Optics offers viewports made from glass, fused silica, sapphire, ZnSe, CVD diamond and many more as well as a variety of flanges. All setups are designed to withstand the vacuum pressure and maintain optical clarity. They are sealed with high-quality, vacuum-compatible gaskets or welds to ensure they do not leak.
These viewports are essential in various fields, including materials science, semiconductor manufacturing, and fundamental physics research, where maintaining a controlled vacuum environment is crucial.
Zinc Selenide (ZnSe) Viewports
Zinc Selenide (ZnSe) Viewports
Firebird Optics’ Zinc Selenide (ZnSe) viewports are designed for high-performance vacuum applications requiring excellent infrared (IR) transmission and long-term durability. With broad transmission from the visible into the far-infrared, these viewports are ideal for CO₂ laser systems, thermal imaging, and IR spectroscopy where high optical clarity and minimal absorption are essential. Their strong resistance to thermal shock and stable performance in vacuum environments make them well-suited for semiconductor processing, research, and industrial applications. Available in CF, KF, and ISO flange configurations, Firebird Optics’ ZnSe viewports integrate easily into a wide range of systems and can be fully customized to customer specifications, including size, thickness, coatings, and mounting options for optimized performance.
Zinc Selenide (ZnSe) Viewports for Vacuum Systems: Specifications, Applications, and Flange Selection Guide
Zinc Selenide (ZnSe) viewports are high-performance optical windows designed for vacuum and ultra-high vacuum (UHV) environments where strong infrared (IR) transmission is required. Known for their excellent optical clarity across the visible to far-infrared spectrum, ZnSe viewports are widely used in applications involving CO₂ lasers, thermal imaging, and IR spectroscopy. Their ability to maintain vacuum integrity while providing reliable optical access makes them a critical component in both scientific research and industrial processing systems.
Why Choose Zinc Selenide Viewports?
Zinc selenide is a premium optical material specifically valued for infrared applications. Its key advantages include:
Broad IR Transmission: Extends from visible wavelengths into the far-infrared (up to ~20 µm), making it ideal for IR optics
Low Optical Absorption: Ensures high signal clarity and efficiency in laser and spectroscopy systems
High Laser Compatibility: Particularly well-suited for CO₂ laser wavelengths (10.6 µm)
Thermal Shock Resistance: Performs reliably under rapid temperature changes
Good Chemical Stability: Suitable for use in harsh industrial and vacuum environments
These characteristics make ZnSe viewports the go-to solution for IR-intensive applications where both durability and optical performance are required.
Typical Specifications of Zinc Selenide Viewports
Firebird Optics’ ZnSe viewports are engineered to meet the demanding requirements of vacuum systems and precision optics. Typical specifications include:
Material: Optical-grade Zinc Selenide (ZnSe)
Transmission Range: ~0.5 µm to 20 µm (visible to far-IR)
Surface Quality: 60/40 scratch-dig (standard optical grade)
Flatness: Up to 1λ @ 632 nm (typical for precision optics)
Leak Rate: ≤ 1 × 10⁻¹⁰ mbar·L/s (He)
Pressure Range: Atmosphere to UHV (~10⁻⁹ to 10⁻¹¹ mbar depending on flange type)
Operating Temperature: Up to ~120–200°C depending on sealing method
Flange Materials: Stainless steel (304L, 316L/316LN)
Coatings: Optional anti-reflective (AR) coatings for optimized IR transmission
Custom sizes, thicknesses, and coatings are available to meet specific system requirements.
Applications of Zinc Selenide Viewports
Infrared Laser Systems
ZnSe viewports are widely used in CO₂ laser systems, where their high transmission at 10.6 µm ensures efficient beam delivery and minimal energy loss.
Thermal Imaging & FLIR Systems
Due to their excellent IR transmission, ZnSe viewports are commonly used in thermal imaging and infrared (FLIR) systems.
Infrared Spectroscopy
ZnSe is ideal for IR spectroscopy applications, enabling accurate measurement and analysis across a wide spectral range.
Semiconductor & Vacuum Processing
These viewports provide reliable optical access in vacuum chambers, plasma systems, and semiconductor processing equipment, where stable IR monitoring is required.
Industrial & Research Environments
ZnSe viewports are extensively used in research laboratories and industrial systems requiring precise IR optical measurements under vacuum conditions.
Flange Options: CF vs KF vs ISO
Selecting the appropriate flange type is essential for ensuring compatibility with your vacuum system. ZnSe viewports are available in CF, KF, and ISO configurations, each suited to different applications.
CF (ConFlat) Flanges – For Ultra-High Vacuum (UHV)
Seal Type: Metal-to-metal seal using copper gasket
Vacuum Range: UHV (down to ~10⁻¹¹ mbar)
Temperature Capability: Highest bake-out performance
Best Applications:
Semiconductor manufacturing
Surface science
High-energy physics
Permanent vacuum systems
Why choose CF?
CF flanges provide the most reliable and leak-tight seal, making them ideal for critical UHV environments requiring long-term stability.
KF (Quick Flange) – For Flexible Vacuum Systems
Seal Type: Elastomer O-ring with clamp
Vacuum Range: Rough to high vacuum
Temperature Capability: Moderate
Best Applications:
Laboratory setups
R&D environments
Systems requiring frequent assembly/disassembly
Why choose KF?
KF flanges allow for fast installation and removal, making them ideal for modular and experimental systems.
ISO Flanges – For Large Vacuum Systems
Seal Type: O-ring or bolted flange system
Vacuum Range: High vacuum
Temperature Capability: Moderate
Best Applications:
Large vacuum chambers
Industrial processing systems
Applications requiring larger viewing areas
Why choose ISO?
ISO flanges are designed for large-scale vacuum systems, offering strong mechanical support and scalability.
Custom Zinc Selenide Viewports
Firebird Optics offers customizable ZnSe viewports tailored to specific application needs, including:
Custom diameters and thicknesses
Anti-reflective coatings for specific IR wavelengths
Specialized flange materials and configurations
Integration into complex vacuum assemblies
Customization ensures optimal performance for applications ranging from laser systems to advanced IR sensing technologies.
| Flange Type | Flange OD | View Diameter | Optic Thickness | Max Temperature |
|---|---|---|---|---|
| CF Flange ZnSe Viewports | ||||
| NW16CF | 34 mm / 1.33" | 15 mm / 0.60" | 1.5 mm / 0.06" | 120°C |
| NW35CF | 70 mm / 2.75" | 32 mm / 1.26" | 3.0 mm / 0.12" | 120°C |
| NW35CF Large Area | 70 mm / 2.75" | 38 mm / 1.50" | 3.5 mm / 0.14" | 120°C |
| NW63CF | 114 mm / 4.50" | 63 mm / 2.49" | 5.0 mm / 0.20" | 120°C |
| NW100CF | 152 mm / 6.00" | 89 mm / 3.51" | 6.0 mm / 0.24" | 120°C |
| NW150CF | 203 mm / 8.00" | 136 mm / 5.36" | 9.5 mm / 0.38" | 120°C |
| NW200CF | 254 mm / 10.00" | 136 mm / 5.36" | 9.5 mm / 0.38" | 120°C |
| KF Flange ZnSe Viewports | ||||
| KF16 | 30 mm / 1.20" | 15 mm / 0.60" | 1.5 mm / 0.06" | 120°C |
| KF25 | 40 mm / 1.60" | 15.5 mm / 0.62" | 1.5 mm / 0.06" | 120°C |
| KF40 | 55 mm / 2.20" | 32 mm / 1.26" | 3.0 mm / 0.12" | 120°C |
| KF40 Large Area | 55 mm / 2.20" | 38 mm / 1.50" | 3.5 mm / 0.14" | 120°C |
| KF50 | 75 mm / 3.00" | 38 mm / 1.50" | 3.5 mm / 0.14" | 120°C |
| ISO Flange ZnSe Viewports | ||||
| ISO63 | 95 mm / 3.80" | 38 mm / 1.50" | 3.5 mm / 0.14" | 120°C |
| ISO100 | 130 mm / 5.20" | 63 mm / 2.49" | 5.0 mm / 0.20" | 120°C |
| ISO160 | 180 mm / 7.10" | 89 mm / 3.51" | 6.0 mm / 0.24" | 120°C |
