This is a G063071331 22.4 mm Dia. N-BK7 Mounted Plano-Concave Lens, with a focal length (EFL) of -50mm, sourced from Qioptiq Photonics. The lens is currently in stock and available for purchase through their website.
The lens is of the Spherical type, specifically a Plano-Concave lens with a Sub Type of Spherical Lens. It has a base shape of Circular and a diameter of 22.4mm. The center thickness of the lens is 1.5mm. The lens's inner and outer radii are both zero, indicating a uniform curvature.
The lens is made of N-BK7 Schott material, a common type of glass used in optical applications due to its excellent optical properties. The lens is designed to operate at a wavelength of 588nm.
The lens features a coating on both the front and back surfaces. The front coating is Qio Al Ralvis Aoi 45, and the back coating is also Qio Al Ralvis Aoi 45. This coating is likely designed to enhance the lens's performance in specific applications, such as reducing reflection or increasing transmission.