Custom Optical Windows | Sapphire, Fused Silica, BK7 & IR Materials | Microwork

Custom Optical Windows

Precision optical windows for UV, visible, NIR, IR, laser and harsh-environment applications.

Microwork supplies custom optical windows made from sapphire, fused silica, BK7, quartz, silicon, germanium, zinc selenide and calcium fluoride for UV, visible, NIR, IR and laser applications.

Optical windows are used to protect optical systems while maintaining transmission, flatness, surface quality and environmental stability. Depending on the application, the window may need to resist thermal load, pressure, abrasion, corrosion, laser energy, vacuum conditions or mounting stress.

Material selection should be based on wavelength range, transmission requirement, mechanical strength, thermal stability, chemical resistance, coating compatibility and cost target. For demanding environments, sapphire may be selected for its hardness, chemical resistance and durability, while fused silica, BK7 and IR materials may be more suitable depending on optical and wavelength requirements.

Custom sizes, thicknesses, surface quality, flatness, parallelism, chamfer and coating requirements can be reviewed based on your drawing and operating conditions.

Available Window Materials

Common optical window materials include:

• Sapphire – high hardness, chemical resistance and mechanical durability
• Fused silica / quartz – good UV transmission and thermal stability
• BK7 – cost-effective optical glass for visible and near-IR applications
• Silicon – commonly used for selected IR applications
• Germanium – IR optical material for thermal imaging and infrared systems
• Zinc selenide (ZnSe) – IR transmission material, often used in CO2 laser optics
• Calcium fluoride (CaF2) – UV to IR transmission material for optical systems

Material selection can be reviewed according to wavelength range, environment, coating requirements and mechanical design.

Typical Specifications：

Material: Sapphire, fused silica, BK7, quartz, silicon, germanium, ZnSe, CaF2 or other optical materials
Shape: Round, square, rectangular, stepped, wedged or custom-shaped windows
Dimensions: Custom sizes available upon drawing review
Thickness tolerance: Custom tolerance available depending on material and design
Surface quality: 60/40, 40/20 or 20/10 depending on optical requirement
Flatness: Custom flatness available depending on size, material and surface type
Parallelism: Custom parallelism available upon requirement
Edge finish: Fine ground, chamfered or polished edges
Coating: AR coating, dielectric coating or custom coating options

Engineering Considerations：

When selecting an optical window, engineers should consider wavelength range, transmission requirement, surface quality, flatness, parallelism, coating durability, thermal load, pressure, chemical exposure, edge condition and mounting stress.

For protective windows, mechanical durability and sealing conditions may be more important than optical precision. For imaging, laser, spectroscopy or sensor applications, surface quality, flatness, coating performance and material transmission become critical.

Optical window cost and manufacturability are strongly affected by material choice, diameter or length, thickness, flatness, surface quality, coating requirement and edge design. Thin windows, high flatness, tight parallelism, IR materials and special coatings should be reviewed carefully before quotation.

Sapphire vs Glass Optical Windows：

Sapphire windows are often selected when scratch resistance, mechanical strength, chemical resistance and high-temperature stability are important. They are suitable for harsh environments, sealing windows, protective viewports and demanding industrial systems.

BK7 and fused silica windows may be more cost-effective for standard optical systems where extreme mechanical durability is not required. Fused silica can be preferred for UV transmission and thermal stability, while BK7 is commonly used for visible and near-infrared applications.

For IR applications, materials such as silicon, germanium, ZnSe or CaF2 may be more suitable depending on wavelength range and system design.

Need a Custom Optical Window?

Send us your drawing, target material, wavelength range, surface quality, flatness, coating requirement, thickness tolerance and operating conditions. We can help review material suitability, manufacturability and key technical risks before quotation.