37-431 25mm Dia. N-BK7 Precision Aspheric Lens; EFL=50mm; NA=0.25 Uncoated

This is a high-precision aspheric lens from the renowned optical components vendor, Edmund Optics. The lens, catalog number 37-431, is a N-BK7 Schott material type, specifically designed for use at a wavelength of 587.6 nm.

The lens features a circular base shape with a diameter of 25 mm. The edge thickness is 4.14 mm, and the effective focal length (EFL) is 50 mm. The lens's first radius of curvature (R1) is 25.84 mm, while the second radius (R2) is 0 mm. The back focal length (BFL) is 45.23 mm. The center thickness is 7.24 mm, and the lens has a numerical aperture (NA) of 0.25.

The lens is uncoated, which means it does not have any anti-reflective or other coatings applied to its surfaces. This can be beneficial in certain applications where specific coatings may interfere with the desired optical performance. However, it's important to note that uncoated lenses can have higher reflectivity, which may need to be considered in the overall system design.

The lens's geometry is defined by aspheric coefficients, including k1 (-0.800424), with higher-order coefficients (k2, k3, etc.) being zero. This aspheric design can help reduce spherical aberration and other optical aberrations, providing superior image quality compared to traditional spherical lenses.