This is the 37-423 model from Edmund Optics, a high-precision aspheric lens with a 20mm diameter and a numerical aperture of 0.8. The lens is made from N-SF6 Schott, a high-refractive index glass, and is uncoated.
The lens has an effective focal length (EFL) of 12.5mm, making it suitable for applications that require a short focal length. The inner radius of the lens is 0, while the outer radius is also 0, indicating a symmetrical design. The lens has a thickness of 5.01mm at the edge and 10.5mm at the center.
The aspheric design of the lens is defined by its radius of curvature (r1) of 10.065mm and a conic constant (k1) of -1.206658. The lens has no secondary radius of curvature (r2), indicating a single curvature surface. The lens's back focal length (BFL) is 6.68mm.
The lens is designed to operate at a wavelength of 587.6nm. It is important to note that the lens is uncoated, which may affect its performance in high-intensity light applications or where low reflectivity is required.