
This is a Germanium Plano-Convex lens, sourced from Alkor Technologies, with a diameter of 50.8 mm and a focal length of 50.8 mm. The lens is uncoated, which means it does not have any additional layers to protect or enhance its optical properties.
The lens's geometry is characterized by a thickness of 2 mm at the edge and 4.2 mm at the center. The inner and outer radii are both zero, indicating a simple spherical shape. The lens's material is identified as germanium burnett, and it is designed to work with a wavelength of 10600 nm.
The lens's type is spherical, and it is sub-typed as a Plano-Convex lens, which means one side is flat (plano) and the other side is curved (convex). This type of lens is often used to focus or collimate light in various optical systems.
For more information about this lens, you can refer to the vendor's website at http://www.alkor.net/germanium_lenses.html. The website indicates that the lens is currently in stock, suggesting that it is readily available for purchase.