BK7 Window


Products Description:custom as your require


Windows are often used to create a physical barrier between two different environments – preventing two gases from mixing together, separating liquids from air, keeping a sealed system in vacuum. In many optical systems, a window is used to protect more expensive optical components from back-splatter, out-gassing or other possible damage.

From prototype to production, Focus Technology manufactures and delivers precision grade and commercial quality windows to address applications in the ultraviolet (UV), visible, and infrared (IR) wavelength ranges.

Technical Parameters


BK7 Grade A Optical Glass

Typical Diameter (Φmm)

8.0, 10.0, 12.7, 15.0, 20.0, 25.4, 30.0, 50.8

Typical Thickness (mm)

0.5, 1.0, 2.0, 3.0, 5.0, 6.0

Diameter Tolerance (mm)

+/-0.2 (General), +0.0/-0.02 (High Precision)

Thickness Tolerance (mm)

±0.2 (General), ±0.05 (High Precision)

Clear Aperture

>80% (Small Size), >95% (Large Size)


3 min. (General), 3 sec. (High Precision)

Surface Quality

80/50 (General), 10/5 (High Precision)

Flatness (per 25mm@633nm)

λ(General), λ/10 (High Precision)

Bevel (face width x 450)



Uncoated, AR, HR, PR, Coating, etc.

Note for Window:

(1). Windows made from materials such as N-BK7, Fused Silica, Sapphire, CaF2, Silicon, Borofloat, or other optical glass supplied by Schott and Chinese CDGM are available upon request.

(2). Custom-made windows at any size from Φ2.0mm to Φ350mm clear aperture are available, apart from round, windows at shape of square, triangular, or other shapes are also available.

(3). Thickness from 1.0mm to 50.0 mm is available as request.

(4). 95% clear aperture is available upon request.

(5). Better bevel is available as request.

(6). Windows with Anti-Reflective (AR), High-Reflective (HR), Partial-Reflective (PR) coating are available.

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