LB1212-B N-BK7 Bi-Convex Lens; Dia:9.0 mm; f=20.0 mm ARC 650-1050nm

The LB1212-B is a high-quality bi-convex lens from Thorlabs, designed with a diameter of 9.0 mm and a focal length of 20.0 mm. This lens is made from N-BK7, a popular glass type from Schott, known for its excellent optical properties. The lens features an Anti-Reflection coating (ARC) designed for the wavelength range of 650-1050nm, making it suitable for a wide range of applications, including but not limited to, beam shaping, focusing, and imaging.

The lens has a center thickness of 2.8 mm and an edge thickness of 1.8 mm, providing a robust structure while maintaining a low profile. The radii of curvature for the front and back surfaces are 20.1 mm and -20.1 mm, respectively, contributing to the lens's overall optical performance. The back focal length (BFL) is 19 mm, and the effective focal length (EFL) is 20 mm, which is the distance from the lens's principal plane to the focus point of the lens.

The LB1212-B lens is available with a broadband anti-reflection coating on both the front and back surfaces, reducing reflection losses and increasing transmission. This coating is designed to provide high transmission across the specified wavelength range.