Compare Model Drawings, CAD & Specs Availability Price
Cylindrical Lens, Plano-Concave, N-BK7, 25.4x6.35mm, -6.4mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 25.4x12.7mm, -12.7mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 25.4x12.7 mm, -25 mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 50.8x19 mm, -50 mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 50.8x25.4 mm, -75 mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 50.8x25.4mm, -100mm FL, Uncoated
Cylindrical Lens, Plano-Concave, N-BK7, 50.8x25.4mm, -150 mm FL, Uncoated
In Stock
In Stock
Cylindrical Lens, Plano-Concave, N-BK7, 50.8x25.4mm, -200 mm FL, Uncoated


  • Lens Type
  • Lens Shape
  • Lens Material
    Grade A N-BK7
  • Antireflection Coating
  • Centration
    <3 arc min
  • Size Tolerance
    ±0.1 mm
  • Focal Length Tolerance
  • Center Thickness Tolerance
    +0.5/-0.25 mm
  • Edge Thickness Tolerance
    ±0.3 mm
  • Clear Aperture
    ≥central 80% of dimensions
  • Chamfers
    0.5 mm face width
  • Chamfers Angle/Tolerance
    45°, typical


N-BK7 Substrates for VIS and NIR Applications

N-BK7 is an excellent lens material for most visible and near infrared applications. It is the most common borosilicate crown optical glass, and it provides great performance at a good value. Its high homogeneity, low bubble and inclusion content, and straightforward manufacturability make it a good choice for transmissive optics. N-BK7 is also relatively hard and shows good scratch resistance. The transmission range for BK 7 is 380 to 2100 nm. It is not recommended for temperature sensitive applications, such as precision mirrors. For more information, refer to our optical materials technical note.

Precision Uncoated Cylindrical Lens Surfaces

Our N-BK7 precision cylindrical lenses are designed to meet the demanding requirements of laser electro-optic applications. They are manufactured from fine annealed optical glass and are polished to tight tolerances to ensure minimum wavefront distortion. Tight surface quality tolerances minimize scatter and unwanted diffraction effects, making these lenses especially well suited for sensitive laser applications, including laser scanning, diode laser beam shaping. Additional applications include focusing light into a thin line for optical metrology or collecting light in spectroscopy systems. They can also be used to expand the output of a laser diode into a symmetrical beam.

Circularize a Laser Diode Beam Profile

In a typical laser diode (a P-i-N diode), electrical current flows vertically between contacts on top of and below the semiconductor material substrate. Charge carrier combination and the resulting light emission occurs in the intrinsic region between the doped electrodes. A horizontal optical cavity is formed by cleaving the substrate and polishing the side faces. Fresnel surface reflections at these faces create optical feedback resulting in a lasing effect. Light emitted from a rectangular aperture typically takes on an elliptical beam profile with angle θ1 and θ2 along the major and minor axes. Two cylindrical lenses with focal lengths f2/f1 = θ1/θ2, each positioned their focal length away from the laser diode, may be used to produce a circular collimated beam output.

Generating a Line of Light from a Collimated Laser

A common application of plano-concave cylindrical lenses is shown to the right. A collimated laser beam of radius r0 is incident upon a cylindrical plano-concave lens of focal length -f. In this figure, the radius of the laser beam is exaggerated for clarity. The laser beam will expand with a half-angle θ of r0/f. The laser beam will appear to be expanding from a virtual source placed a distance f behind the lens. At a distance z after the lens, there will be a line with thickness 2r0 (ignoring expansion of the Gaussian beam) and length L = 2 (r0/f)(z+f). If z is large compared to f, then we have an expansion ratio that is very close to z/f. This is not an imaging problem; we are projecting the laser beam into a line at a particular distance. The length of the line is simply proportional to z.

Cylindrical Lens Rotation Adapters

Our CYH Series Cylindrical Lens Rotation Adapters have been designed to accommodate the special geometry of cylindrical optics. The holders consist of a lens base that centers the lens in the holder and a knurled retaining ring to hold the lens in place. The inner face of the retaining ring is a Delrin washer that contacts the lens surface. This configuration avoids the possibility of a point contact between the lens surface and a metal retaining ring. The CYH-1 and CYH-2 fit into LM-R Series mounts to provide accurate positioning and easy rotation for cylindrical axis alignment.

Adjustable Cylindrical Lens Mount

Our CYM-2R Adjustable Cylindrical Lens Mount can hold and position cylindrical optics as large as 2-in in height. What makes this mount unique is its ability to rotate a cylindrical optic about its center. This feature eliminates unwanted translation during rotation of the power axis.

Lens Dimensions 50.8 x 50.8 mm 50.8 x 25.4 mm 50.8 x 19.05 mm 25.4 x 12.7 mm 25.4 x 6.35 mm
OM-cym_2R_group2 CYM-2R CYM-2R w/
CYM-2R w/
CYM-2R w/
CYM-2R w/
OM-cyl_lens_mb-S N/A CYH-2 CYH-2 CYH-1 CYH-1