LD2297-B N-SF11 Bi-Concave Lens; Dia:25.4 mm; f=-25.0 mm ARC 650-1050nm

The LD2297-B is a high-quality bi-concave lens offered by Thorlabs, a leading global manufacturer of photonics components. This lens is designed with a spherical surface on both sides, featuring a base shape of a circle. The lens has a diameter of 25.4 mm and a thickness of 7.2 mm at the edge, while the center thickness is 3 mm.

The lens's effective focal length (EFL) is -25 mm, indicating that it is a diverging lens, causing incoming light rays to spread out. The back focal length (BFL) is -25.6 mm, and the radius of curvature for both surfaces is -39.6 mm, contributing to the lens's diverging properties.

The LD2297-B is made of N-SF11 Schott glass, a high-index, low-dispersion material often used in applications where high numerical aperture (NA) and excellent optical performance are required. This lens is designed to work within the wavelength range of 650-1050 nm, making it suitable for near-infrared (NIR) applications.

The lens features broadband anti-reflection (BBAR) coatings on both the front and back surfaces, with a specified range of 650-1050 nm. These coatings help minimize surface reflections, thereby increasing transmission and improving overall system performance.