Custom Sapphire Optical Window
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High Hardness Sapphire Window | UV-Vis-IR Transparent | Pressure & Seawater Resistant Felix Glass supplies custom single-crystal sapphire optical windows for underwater ROV, aerospace, laser, surveillance and rugged sensor systems. Sapphire delivers superior hardness, thermal shock resistance and chemical stability, compatible with AR, DLC and combined AR+DLC coatings. Sapphire Optical Window | Single Crystal Sapphire Single-crystal sapphire (Al₂O₃) is a premium hard optical substrate transmitting from UV through visible, NIR and mid-wave IR. It features outstanding Mohs 9 hardness, seawater corrosion resistance, high pressure bearing capacity and excellent thermal shock performance. Compared with ZnS, fused silica and silicon, sapphire is the preferred choice for long-life subsea, abrasive and high-reliability airborne applications. Material substrate does not equal final performance grade. Specify wavelength, pressure rating and coating for accurate quotation. Interferometer Inspection Precision Polishing Finished Sapphire Window All sapphire windows are inspected for surface figure, transmittance and scratch-dig quality. Pressure testing is available for subsea-rated components. AR coating boosts transmission for target wavebands. DLC coating adds extra scratch and chemical resistance for marine and sandy environments. AR+DLC combined coating is recommended for subsea sapphire windows where both high transmission and ruggedness are required. Learn more about infrared optical coating technology. To generate an accurate quotation within 24 hours, please prepare below information: Sapphire is Mohs 9 hard, seawater resistant and pressure-capable. ZnS is soft and prone to moisture attack; fused silica lacks mid-IR transmission for thermal imaging. Sapphire cuts off around 5μm. It is not suitable for pure LWIR thermal-only systems; ZnS is the standard for 8–14μm thermal imaging. Yes. We can drill, counterbore, machine O-ring grooves and stepped flanges per your drawing, with full inspection after precision machining.
Custom Sapphire Optical Window Manufacturer
OEM Manufacturing | AR / DLC Coating | Custom SpecificationsMaterial & Grade Overview
Key Specifications & Custom Options
Substrate Material
Single Crystal Sapphire (Al₂O₃)
Shape
Round window, square / rectangular plate, disc, blanks, custom profile
Size Range
Dia 5mm‑300mm, custom thickness, edge flange & O-ring groove
Surface Quality
20‑10 /40‑20 scratch‑dig, customized per customer drawing
Working Wavelength Band
0.2–5.0μm, UV / Vis / NIR / MWIR broadband transmission
Coating Options
Uncoated, UV AR, VIS-NIR AR, MWIR AR, DLC hard coating, AR+DLC combined
Custom Machining
Chamfer, drilling, counterbore, O-ring groove, stepped flange, edge polishing
Inspection
Interferometer, spectrophotometer, hydrostatic pressure test optional, material certificate available
Manufacturing & Inspection Evidence
Typical Application
Coating Selection Guide
Order & Quotation Requirements (Valid RFQ Checklist)
Send Drawing For Quote
FAQ Snippets
Why choose sapphire instead of ZnS or fused silica for subsea?
Does sapphire transmit 8–14μm LWIR thermal band?
Can you machine sapphire windows with holes and O-ring grooves?
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