This is the 16-989 model from Edmund Optics, a high-precision aspheric lens with a 50mm diameter and a numerical aperture of 0.66. The lens is designed for use in the near-infrared spectrum, specifically between 600 and 1050nm.
The lens is made from N-SF5 Schott, a high-refractive index glass that is often used in optical systems requiring high numerical apertures. The aspheric design of the lens helps to reduce spherical aberration, a common issue in traditional spherical lenses, resulting in improved image quality and resolution.
The lens has an effective focal length (EFL) of 37.5mm, which is the distance from the lens's principal point to the image plane when the lens is focused at infinity. The lens's thickness at the edge is 7.47mm, while its thickness at the center is 21.34mm. The front and back surfaces of the lens are coated with Edmund Optics' NIR-Plus 600-1050nm coating, which enhances its transmission in the near-infrared spectrum.
The lens's geometry includes a range of parameters that define its shape and curvature. The inner radius is 0mm, while the outer radius is also 0mm. The lens's front and back focal lengths are 4.967341e-06mm and 4.493814e-10mm, respectively. The lens's conic constant (k1) is -1.187653, and its aspheric coefficients (k2, k3, k4, k5, k6) are all 0.