Precision Optical Components for Underwater Imaging & Subsea Systems
Sapphire Windows Optical-grade sapphire windows for extreme marine & subsea environments
Sapphire Windows

Optical-grade sapphire windows for extreme marine & subsea environments

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Sapphire Windows

Knight Optical’s Sapphire Windows are engineered for oceanographic and offshore systems demanding optical clarity and maximum resilience. Fabricated from crystalline Al₂O₃, these windows withstand punishing subsea conditions—resisting intense pressure, thermal variation, saltwater corrosion, and high-energy radiation.

With optical transmission from 150nm to 5.5µm and a hardness second only to diamond, they are ideally suited for high-precision sensing, imaging, and laser-based instrumentation in challenging marine environments.

Available in both c-cut and random-cut configurations, the windows meet distinct application needs: c-cut for low-birefringence and minimized image distortion, and random-cut for robust mechanical integrity in non-critical optics.

Knight Optical also offers extensive customization, from precision edge finishing and optical coatings (including BBAR and DLC) to integration into sealed sub-assemblies. Each unit is individually inspected using in-house metrology to guarantee superior optical fidelity and mechanical tolerances, meeting the exacting requirements of scientific and industrial subsea deployments.

Frequently Used Specifications
Diameter Range <5mm to 300mm
Diameter Tolerance ±0.1mm
Centre Thickness Up to 50mm
Thickness Tolerance ±0.05mm
Clear Aperture 90%
Centration Tolerance <1 arc minute
Form Error <λ/4 @ 633nm over aperture
Surface Radius Tolerance <1 fringe over aperture
Linear Dimension Up to 120mm
Linear Tolerance ±0.1mm
Angular Tolerance <5 arc minutes
Surface Quality 40-20 scratch/dig
Coatings Available BBAR @ 1–5µm, DLC @ 1–5µm
Edge Finish Ground, blacked
Chamfer 0.3 x 0.3mm @ 45°
Material Sapphire (Al₂O₃), HK1370kg/mm²
Transmission Range 0.15µm to 5.5µm
Refractive Index 1.75