The LB1889-A is a high-quality bi-convex lens from Thorlabs, designed for use in a wide range of optical applications. This lens is made from N-BK7, a popular glass type known for its excellent optical properties, and is specifically designed for use in the 350-700nm wavelength range.
The lens features a diameter of 2 inches (50.8mm) and a focal length of 250.0mm, providing a high level of magnification and precision. The lens is 3mm thick at the edge and 5.5mm thick at the center, providing a robust and durable design. The effective focal length (EFL) of the lens is 250mm, and the back focal length (BFL) is 248.2mm.
The lens is coated with a broadband anti-reflection coating (ARC), which is designed to reduce surface reflections and increase transmission. This coating is applied to both the front and back surfaces of the lens, ensuring optimal performance in a variety of lighting conditions.
The lens is spherical in shape, with a first radius of curvature (R1) of 256.6mm and a second radius of curvature (R2) of -256.6mm. The inner and outer radii are both 0mm, indicating a uniform curvature across the entire lens surface.