This is a Plano-Concave Lens, a type of spherical lens, sourced from Alkor Technologies. The lens has a base shape of a circle and a diameter of 25.4 mm. The thickness at the center of the lens is 2 mm. The effective focal length (EFL) of this lens is -76.2 mm, indicating that it is a diverging lens.
The lens is made of Calcium Fluoride (CaF2) with the material ID mal-1963. This material is known for its excellent transparency in the ultraviolet, visible, and near-infrared regions of the spectrum. The lens is uncoated, meaning it does not have any additional layers to enhance its optical properties.
The lens is designed to work with a wavelength of 5000 nm. It is important to note that the inner and outer radii of the lens are both 0, indicating that this lens does not have any curvature on its inner or outer surface.
For more detailed information, please refer to the vendor's website at http://www.alkor.net/CaF2_plano_concave_lenses.html. The website indicates that the lens is currently in stock, ensuring quick delivery for your optical needs.