49-326 12.5 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=40mm VIS-NIR 400-1000nm

The 49-326 is a high-quality achromatic doublet lens from Edmund Optics, designed for use in the visible (VIS) and near-infrared (NIR) spectrum, specifically between 400-1000nm. This lens is characterized by its 12.5 mm diameter and effective focal length (EFL) of 40mm, making it suitable for a wide range of optical applications.

The lens is composed of two elements, made from N-BK7 and N-SF5 Schott glass, respectively. These materials were chosen for their excellent optical properties, including low dispersion and high transmission in the specified wavelength range. The first element has a radius of curvature (R1) of 24.77mm, while the second element has an R2 of -18.01mm and an R3 of -51.17mm. The center thickness of the lens is 3.73mm, with an edge thickness of 3.88mm.

The lens is coated with Edmund Optics' VIS-NIR coating (edm visnir0sp2002000) on both the front and back surfaces. This coating is designed to enhance the lens's performance by reducing surface reflections and improving transmission. The coating is applicable for the full specified wavelength range.

The 49-326 is a multiplet lens, meaning it is composed of multiple elements. This design allows for the correction of chromatic aberrations, a common issue in optical systems where different wavelengths of light are focused at different points. By using an achromatic doublet, the 49-326 provides sharper images with reduced color fringing.