The 68-015 is a double-concave lens with a diameter of 25mm and a focal length of -25mm, making it a powerful tool for applications that require a highly curved optical path. This lens is sourced from Edmund Optics, a reputable vendor known for their high-quality optical components.
The lens is made from n-SF11 Schott, a high-index glass with excellent optical properties. This material is particularly suitable for use in the near-infrared (NIR) region, as indicated by the NIR II coating on both the front and back surfaces. This coating is designed to enhance the lens' performance in the 750-1550nm wavelength range, making it ideal for a wide range of NIR applications.
The geometry of the lens is carefully designed to provide optimal performance. The inner and outer radii are both zero, indicating a simple spherical shape. The thickness at the edge of the lens is 6.05mm, while the thickness at the center is 2.5mm. The back focal length (BFL) is -25.69mm, slightly longer than the focal length due to the curvature of the lens.