Features
• Four Sizes Available
• Ø1/2″: 3.0 mm Thick
• Ø1″: 1.0 mm or 5.0 mm Thick
• 25 mm x 36 mm: 1.0 mm Thick
• Ø2″: 12.0 mm Thick
• Available Uncoated or with One of Three Broadband AR Coatings
• 350 – 700 nm (-A Coating Designation)
• 650 – 1050 nm (-B Coating Designation)
• 1050 – 1700 nm (-C Coating Designation)

Thorlabs’ N-BK7 High-Precision Windows are available in Ø1/2″, Ø1″, 25 mm x 36 mm, and Ø2″ sizes. They are available uncoated for the 350 nm – 2.0 μm range or with one of our three low-loss standard broadband antireflection (AR) coatings deposited on both surfaces: -A (350 – 700 nm), -B (650 – 1050 nm), or -C (1050 – 1700 nm). While uncoated windows have typical losses of about 4% per surface, the AR coatings reduce this to Ravg < 0.5%. These AR coatings provide good performance for angles of incidence (AOI) between 0° and 30°. For additional information on these coatings, please see the Graphs tab. The Ø1" windows are available with a 1.0 mm or 5.0 mm thick substrate. The 1.0 mm thick windows are ideal for ultrafast applications or in situations where space is limited. We recommend mounting the thin windows in our LMR1 or LMR1/M Fixed Lens Mount and securing them with a SM1LTRR Stress-Free Retaining Ring. N-BK7 provides excellent transmission in the visible and near infrared portions of the spectrum. It is typically chosen whenever the additional benefits of UV fused silica (i.e., good transmission further into the UV and a lower coefficient of thermal expansion) are not necessary. Options : infrared, precision, BK7, fused silica, standard