AC508-200-C-ML 50.8 mm Dia. N-LAK22/N-SF6HT Mounted Achromatic Doublet; EFL=200mm 1050-1700nm

The AC508-200-C-ML is a mounted achromatic doublet lens, designed and manufactured by Thorlabs. This lens is specifically engineered for use within the 1050-1700nm wavelength range, making it suitable for a variety of applications within the near-infrared spectrum.

The lens features a 50.8mm diameter, offering a substantial surface area for light transmission. It boasts a focal length of 200mm, as indicated by its EFL (Effective Focal Length) rating. This combination of a large diameter and long focal length allows for a wide field of view and high magnification, respectively.

The lens is constructed from two types of Schott glass, N-LAK22 and N-SF6HT. These materials were chosen for their specific refractive indices and dispersion properties, which contribute to the lens's achromatic design. This design ensures that the lens minimizes chromatic aberration, a common issue in optical systems where different wavelengths of light are focused at different points.

The lens is coated with Thorlabs' proprietary AC1050-1700-C coating on both the front and back surfaces. This coating is designed to enhance the lens's performance within the 1050-1700nm wavelength range, improving transmission and reducing reflection.

The lens geometry is complex, with three radii of curvature (r1, r2, r3) and varying thicknesses at the edge, center 1, and center 2. This geometry contributes to the lens's overall performance, particularly in terms of its imaging capabilities.