This is a Plano-Concave lens, type of spherical lens, offered by Qioptiq Photonics. It has a base shape of a circle and a diameter of 22.4 mm. The lens's center thickness is 1.5 mm, and it has an effective focal length (EFL) of -50 mm at a wavelength of 1064 nm. The front and back surfaces of the lens have a radius of curvature of -25.483 mm and 0 mm, respectively.
The lens is made of UVFS material with the Mal-1965 ID. It comes with a coating of Qio HP Nbar Arhs-Yag on both the front and back surfaces, which is suitable for use at a wavelength of 355 nm.
The lens's geometry is spherical, and it is unmounted and fused silica. According to the vendor's website, this item is currently in stock. For more information and purchasing, users can visit the provided weblink.