45-139 15 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=75mm MgF2 400-700nm

The 45-139 is a high-quality achromatic doublet lens, 15 mm in diameter, with an effective focal length (EFL) of 75mm. This lens is sourced from the reputable optical vendor, Edmund Optics, and is available for purchase on their website. The product link provided is currently active and indicates that the item is in stock.

The lens is constructed from two types of glass: N-BK7 from Schott and N-SF5 from Schott. This combination is used to correct chromatic aberration, a common issue in optical systems where different wavelengths of light are focused at different points. The achromatic design ensures that the lens focuses both red and blue light at the same point, providing sharper images.

The lens has a base shape of a circle and features a multiplet geometry. The diameter of the lens is 15 mm, and it has a thickness of 6.59 mm at the edge. The inner and outer radii are 0, and the EFL is 75 mm. The first radius of curvature (r1) is 39.61 mm, the second radius (r2) is -36.46 mm, and the third radius (r3) is -145.02 mm. The center thickness is 5 mm, and the center a thickness is 2.5 mm.

The lens is coated with Edmund Optics' standard MgF2 coating on both the front and back surfaces. This coating is designed to provide high transmission in the 400-700 nm range, making it suitable for a wide range of optical applications.