The SLB-20-25N is a Plano-Concave Lens, part of the Spherical Lens category, sourced from OptoSigma. This lens is uncoated and features a base shape of a circle. The lens has a diameter of 20.0 mm and a thickness at the edge of 6.7 mm, while the center thickness is 2.0 mm. The effective focal length (EFL) of this lens is -25.0 mm, making it a negative or diverging lens.
The lens's first radius of curvature (R1) is -12.98 mm, and the back focal length (BFL) is -26.3 mm. The inner radius is 0 mm, and the outer radius is also 0 mm. This lens is made of n-BK7 Schott material, a popular choice for its high refractive index and low dispersion.
The lens is designed to operate at a wavelength of 546.1 nm. The shape of the lens is spherical, a common choice for its ease of manufacturing and versatility. The coating of the lens is not specified, indicating that it is likely uncoated. This lens is currently in stock and available for purchase.