This is a Plano-Convex lens, type LA1172-AB, manufactured by Thorlabs. The lens has a diameter of 25.4 mm and a thickness of 2 mm at the edge, with a center thickness of 2.4 mm. The effective focal length (EFL) of this lens is 398.7 mm, making it suitable for applications requiring long focal lengths.
The lens is made of N-BK7, a popular glass type in the optical industry, known for its excellent optical properties and versatility. The curvature of the lens is defined by a radius (R1) of 206 mm on the convex side. The inner and outer radii are both zero, indicating a plano surface on the other side.
The lens is coated with THo AB Bbar on both the front and back surfaces. This anti-reflection coating is designed to reduce surface reflections and increase transmission in the spectral range of 400-1100 nm.
The lens is spherical in shape, a common choice for many optical systems due to its ease of manufacturing and alignment. The lens is currently in stock, according to the vendor's website.