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Biconcave Lens

Name: Biconcave Lens
Place of Origin: Shaanxi, China
Surface quality: 20/10--80/60
Supply Ability: 100000 Piece/Pieces per Month
Description: Biconcave Lens
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Material: K9, BK7, FS, UVFS, CaF₂, ZnSe

Diameter:3mm-200mm±0.05mm

Center Thickness Tolerance:±0.05mm

Lens Alignment Error:≤3min

Surface Accuracy:λ/ 8 @

Surface Quality:40/20. 60/40. 80/60

Effective Caliber: 90%

The Biconcave lens is similar to the plano-concave lens. The focal length is negative, but the parallel incident light diverges outward. The two side surfaces of the double-concave lens have the same radius of curvature, and are generally used for beam expansion and projection.

Example with BK7 material：These N-BK7 biconcave lenses are available uncoated or with one of five antireflection coatings (-A, -AB, -B, -C, or -D), which reduces the amount of light reflected from each surface of the lens (see the Selection Guide table below for coating option). Since approximately 4% of the incident light is reflected at each surface of an uncoated substrate, the application of an AR coating improves transmission, which is important in low-light applications, and prevents the undesirable effects (e.g., ghost images) associated with multiple reflections. Having optics that are AR coated on both surfaces is particularly desirable for applications utilizing multiple optical elements. Please see the Graphs tab for additional coating information.

N-BK7 Biconcave Lens Selection Guide
Coating name	wavelength band
Uncoated	Uncoated
A Coating	350nm-700nm
AB Coating	400nm-1100nm
B Coating	650nm-1050nm
C Coating	1050-1700nm
D Coating	1650nm-3000nm