N-BK7 Plano-Convex Lenses

These Plano-Convex Lenses are fabricated from RoHS-compliant BK7 glass (N-BK7) and feature an antireflection coating for the 1050-1620 nm range. N-BK7 is probably the most common optical glass used for high quality optical components. 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.

These lenses are popular for many applications. They have a positive focal length and near-best-form shape for infinite and finite conjugate applications. Plano-convex lenses focus a collimated | beam to the back focus and collimate light from a point source.

To minimize the introduction of spherical aberration, a collimated light source should be incident on the curved surface of the lens when being focused and a point light source should be incident on the planar surface when being collimated. The focal length of each lens can be calculated using a simplified thick lens equation. f= R/(n-1), where n is the index of refraction and R is the radius of curvature of the lens surface. These lenses are fabricated from N-BK7, which has an Abbe Number of 64.17; this value is an indicator of the dispersion.

These N-BK7 Plano-Convex lenses are available uncoated or with one of three Antireflection Coatings (-A, -B, or -C), which can reduce the amount of light reflected from each surface of the lens. The lenses with a --C coating, which is designed for the 1050-1620 nm range, are highlighted on this page. Lenses with a -A (350-650 nm) or -B (650 - 1050 nm range) antireflection coating are featured elsewhere. Links to these pages are provided in the selection guide table above. Please see the Graphs tab for coating information.

BK7 Plano-Convex Lens Selection Guide
Lens Type Description
Uncoated 350 nm - 2.0 μm range
-A Coating AR coated for the 350 - 650 nm Range
-B Coating AR coated for the 650 - 1050 nm Range
-C Coating AR coated for the 1050- 1620 nm Range
Custom Coatings are also available. Please contact our technical support staff for a quote.

Features
Material: N-BK7
AR-Coated for the 1050-1620 nm Range
Wavelength Range: 350 nm - 2.0 μm (Uncoated)
Choose from 9 Diameters: Ø6 mm, Ø9 mm, Ø1/2" (Ø12.7 mm), Ø18 mm, Ø25 mm, Ø1" (Ø25.4 mm), Ø30 mm, Ø2" (Ø50.8 mm), or Ø75 mm