Cylindrical Lens, Plano-Convex, N-BK7, 25.0 mm, 75 mm FL, 400-700 nm

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.

These round plano-convex cylindrical lenses are designed to mount into standard optical lens mounts.  The round optic shape provides many more mounting options compared to rectangular cylindrical lenses that require special cylindrical lens mounts for mounting.

Our single layer Magnesium Fluoride visible AR coating is the most common choice that offers extremely broad wavelength range at a reasonable price. It is standard on achromats and optional on our N-BK7 plano-convex spherical lenses and cylindrical lenses. Comparing to the uncoated surface, the MgF₂ provides a significant improvement by reducing the reflectance to less than 1.5%. It works extremely well over a wide range of wavelengths (400 nm to 700 nm) at angles of incidence less than 15 degrees.

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.