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Product Announcement

Knight Optical’s Plane Mirrors for Fibre Optic Applications

02 Dec 2021

Available in a variety of materials such as Soda-Lime Float Glass, White Float Glass and BK7 (or equivalent) glass, Knight Optical’s premium range of custom-made and stock Plane Mirrors – commonly referred to as front surface mirrors or first surface mirrors – meet the demanding requirements of multiple applications; whether operating within the ultraviolet (UV), visible, near-infrared (NIR) or far-infrared (FIR) wavebands. The fibre optic division is just one example of a discerning sector benefiting from the high quality of our Plane Mirrors – for devices, for instance, within testing applications to identify signal strength. 

Cost-effective and answering the specific needs of a diverse range of requirements, Knight Optical’s Plane Mirrors are available in four grades from stock – including Precision λ/10, Precision λ/4, 1λ over 25mm and General-Purpose varieties. What’s more, we also provide industry leaders in the fibre optic field with custom-made, high-precision components. A sector favourite, this tailored service allows you to specify the shape, size, substrate and optical coatings (such as Enhanced Aluminium, Ali/SiO2 and Ali/Mgf2) applicable for your end application. 

Typical specs:

Material: Soda-Lime Float Glass, White Plate, BK7 (or equivalent)

Diameter tolerance: +0/-0.2mm

Length/width: ±0.3mm (≤100mm), ±0.5mm (>100mm)

Thickness: ±0.25mm

Surface quality: <60-40 Scratch/Dig (for General-Purpose), <40-20 Scratch/Dig (for λ/4)

Flatness: λ/4 for polished substrates

Stock sheet substrates:

1.1mm-thick: 1λ over 10mm dia. 

3/6mm-thick: 2λ over 25mm dia.

Parallelism: <3 arcmin


  • Enhanced aluminium 94%R for visible applications
  • 99.9% dielectric for laser use in visible applications
  • UV aluminium for UV applications down to 180nm
  • 98.5% dielectric for laser use in the near-infrared (NIR) applications
  • Ion-plated silver for NIR-2000nm applications
  • Protected gold for 750nm to far-infrared (FIR) applications.

First-Class Quality 

Quality is the driving force behind Knight Optical, and to ensure you profit from high-precision optics, we take the utmost care to ensure every component accurately meets your specifications. Offering unparalleled service, Knight Optical undertakes a full inspection of your optics from our ISO 9001:2015-certified, state-of-the-art Metrology Laboratory, followed by a meticulous visual examination by our dedicated QA department. 

To discover how we can enhance your supply chain experience and to learn more about our stock and custom-made Plane Mirrors, contact a member of our technical sales team today. 

UK, Europe, Asia & RoW: E-mail info@knightoptical.co.uk 

Tel +44 (0)1622 859444

USA & Canada: E-mail usasales@knightoptical.com 

Tel +001 401-583-7846 

Knight Optical Ltd
Roebuck Business Park
ME17 1AB
United Kingdom
Tel: 44 (0)1622 859444
Fax: 44 (0)1622 859 555
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