Knight Optical's Sapphire Windows: Unmatched Quality and Performance

06 Mar 2024

Renowned for its exceptional hardness and durability, Sapphire (Al₂O₃) stands as a premier material in the realm of optical components, surpassed only by diamond. Its impressive HK1370kg/mm² hardness is complemented by superior mechanical strength, resistance to thermal and chemical influences, and scratch resistance. These properties make sapphire an optimal choice for applications that demand robust performance under severe conditions.

Sapphire's transmission range extends from ultraviolet (UV) to infrared (IR), spanning 0.15-5.5µm, with a high refractive index of 1.75. This makes it particularly suited for window applications where high radiation resistance is essential across UV to approximately 5µm wavelengths.

At Knight Optical, we offer precision-engineered sapphire windows tailored to meet diverse industry needs. Our most commonly requested specifications are outlined below:

• Diameter Range: <5mm to 300mm
• Diameter Tolerance: ± 0.1mm or better
• Centre Thickness: up to 50mm
• Centre Thickness Tolerance: ± 0.05mm or better
• 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 or better
• Angular Tolerance: ≤5 arc minutes
• Edge Finish: Ground, blacked edges
• Chamfer: 0.3x0.3@45°
• Surface Quality: 40-20 scratch/dig
• Coatings: Broadband Anti-Reflective (BBAR) coating @1-5µm
                  Diamond-Like Carbon (DLC) coating @ 1-5µm

Our commitment to excellence extends beyond our product offerings. Knight Optical's in-house Metrology and Quality Assurance departments ensure each optical component is meticulously inspected and tested, delivering unparalleled quality to your business. For custom requirements, our team is equipped to design and produce bespoke optics that align precisely with your specifications.

Utilising advanced metrological equipment, such as the Zygo Verifire XPZ interferometer for testing surface flatness and irregularities, and the Trioptics PrismMaster for measuring angular tolerances with an accuracy of 3 arc seconds, we maintain the highest standards of precision. Our Agilent Cary 7000 Spectrophotometer and Cary 660 FTIR spectrometer enable comprehensive analysis of transmission and reflection characteristics. In adherence to ISO 10110 and MIL-0-13830A standards, our skilled technicians perform exhaustive visual inspections on all optics, ensuring every component meets or exceeds 10/5 scratch/dig criteria, a critical factor for laser applications.

We are committed to providing our customers with both high-quality products and excellent service. Contact our UK and US teams today and experience true precision, quality and innovation.

Europe, UK, Asia & RoW:

Email:  info@knightoptical.co.uk 

Telephone: +44 (0) 1622 859444

USA & Canada:

Email:  usasales@knightoptical.com

Telephone: +1 401-583-78