LB1889 N-BK7 Bi-Convex Lens; Dia:2 in; f=250.0 mm Uncoated

The LB1889 N-BK7 Bi-Convex Lens is a high-quality optical component sourced from Thorlabs, a leading vendor in the field of precision photonics. This lens, with a diameter of 2 inches and a focal length of 250.0 mm, is designed for use in a wide range of optical systems, including imaging, beam shaping, and laser applications.

The lens is made from N-BK7, a popular glass type known for its excellent optical properties. This material, also known as BK7, is a borosilicate crown glass with a low refractive index and low dispersion, making it an ideal choice for many optical applications. The N-BK7 designation indicates that this particular lens is made from Schott glass, a renowned manufacturer of high-quality optical glass.

The LB1889 lens features a bi-convex geometry, meaning it has a convex shape on both sides. This design provides a high degree of focusing power, making it suitable for use in applications where a tight beam focus is required. The lens has an effective focal length (EFL) of 250.0 mm, which is the distance from the lens to the point where it focuses light.

The lens has a diameter of 50.8 mm (2 inches) and a thickness of 3 mm at the edge, increasing to 5.5 mm at the center. The inner and outer radii are 0 mm, and the back focal length (BFL) is 248.2 mm. The lens is uncoated, meaning it does not have any anti-reflective coatings. However, coatings can be added to enhance the lens's performance in specific applications.