LD1170-B N-BK7 Bi-Concave Lens; Dia:25.4 mm; f=-75.0 mm ARC 650-1050nm

The LD1170-B is a high-quality bi-concave lens from Thorlabs, designed with a base shape of a circle and a sub-type of spherical lens that is concave-concave. This lens is constructed from n-BK7 Schott, a popular optical glass due to its excellent optical properties, making it an ideal choice for various applications.

The lens has a diameter of 25.4 mm and a thickness of 5.6 mm at the edge, reducing to 3.5 mm at the center. It boasts an effective focal length (EFL) of -75 mm, making it suitable for use in optical systems where a negative lens is required. The first radius of curvature (R1) is -77.9 mm, while the second radius (R2) is 77.9 mm, contributing to its bi-concave nature. The back focal length (BFL) is -75.9 mm.

This lens is designed to operate at a wavelength of 587.6 nm, which falls within the visible light spectrum. It features anti-reflection coatings on both the front and back surfaces, specifically THo BBAR, which is optimized for the ARC range of 650-1050 nm. This coating reduces surface reflections, enhancing the overall transmission of the lens.