The LB1056-B is a high-quality bi-convex lens from Thorlabs, designed with a diameter of 1 inch and a focal length of 250.0 mm. This lens is made from N-BK7, a popular glass type from Schott, known for its excellent optical properties and wide transparency range.
The lens features a spherical design, with both surfaces curved outwards. The first surface has a radius of curvature (R1) of 257.1, while the second surface has an R2 of -257.1. This bi-convex design allows for efficient light collection and focusing, making it suitable for a wide range of applications.
The LB1056-B has an effective focal length (EFL) of 250 mm and a back focal length (BFL) of 249.1 mm. The edge thickness is 2 mm, while the center thickness is 2.6 mm, providing excellent structural integrity.
The lens is coated with Thorlabs' BBAR coating on both the front and back surfaces, enhancing its transmission in the 650-1050 nm range. This coating reduces surface reflections, improving the overall efficiency and performance of the lens.