45-215 25 mm Dia. N-BK7/N-SF5 Achromatic Doublet; EFL=300mm MgF2 400-700nm

The 45-215 is a high-quality achromatic doublet lens, sourced from the renowned optical components manufacturer, Edmund Optics. This lens, with a 25 mm diameter, is designed for use in the 400-700nm spectral range, making it suitable for a wide range of optical applications.

The lens is a multiplet, meaning it is composed of multiple optical elements. In this case, it is made up of two different materials: N-BK7 and N-SF5, both from Schott. The use of these materials helps to correct chromatic aberration, a common issue in optical systems, thereby improving the overall image quality.

The lens has an effective focal length (EFL) of 300mm, which is a useful middle-ground between wide-angle and telephoto lenses. This makes it versatile, suitable for a range of applications from imaging to laser beam shaping.

The lens surfaces are coated with Edmund Optics' standard MgF2 coating, which is designed to provide high transmission in the visible spectrum. This coating helps to reduce reflection, thereby improving the efficiency and quality of the optical system.

The lens geometry is carefully designed to provide optimal performance. It has a thickness of 4.88mm at the edge, with a central thickness of 3mm and a thickness of 2.5mm at the edge of the central optical element. The lens also features carefully designed radii of curvature for each optical surface, which are specified as r1=184.84mm, r2=-134.06mm, and r3=-393.98mm.