LE7981-F 25.4 mm Dia. ZnSe Positive Meniscus Lens; EFL=50mm 8-12µm

The LE7981-F is a 25.4 mm diameter Spherical Lens with a Positive Meniscus shape, sourced from Thorlabs. This lens is designed for use in the 8-12 µm wavelength range, making it suitable for a variety of infrared applications. The lens features an effective focal length (EFL) of 50mm, providing a good balance between field of view and focus.

The lens geometry includes an outer diameter of 25.4 mm, a center thickness of 4 mm, and an edge thickness of 3.1 mm. The front and back radii of curvature are 15.5 mm and 16.9 mm respectively, contributing to a back focal length (BFL) of 42.5 mm. The lens is made of ZnSe material, specifically ZnSe Connolly, which is known for its excellent transmission properties in the infrared spectrum.

The LE7981-F is coated with Thorlabs' ZnSe-AR coating on both the front and back surfaces, optimized for the 8-12 µm wavelength range. This coating helps to minimize reflection losses and improve overall transmission, enhancing the performance of the lens in its intended application.