This is a 50mm diameter by 250mm focal length double-convex lens, specifically designed for use in the near-infrared (NIR) spectrum. The lens is sourced from Edmund Optics and is currently in stock. It is made from n-BK7 Schott, a popular optical glass known for its excellent transparency in the visible and near-infrared regions.
The lens features a standard NIR I coating on both the front and back surfaces, which enhances its performance in the 600-1050nm wavelength range. This coating is part of Edmund Optics' NIR I series, which provides high transmission and low reflectance in the NIR spectrum.
The geometry of the lens includes a thickness of 2.5mm at the edge and 4.93mm at the center. The front and back radii of curvature are 257.57mm and -257.57mm respectively, resulting in a back focal length of 248.37mm. The lens has a spherical shape, which is a common choice for its simplicity and wide range of applications.