This is a Plano-Concave Spherical Lens, type HO-PVL50-04B, offered by Holmarc Opto-Mechatronics. The lens has a diameter of 50mm and a center thickness of 2.5mm. The effective focal length (EFL) of this lens is -200mm, making it a negative or diverging lens.
The lens is made of N-BK7, a popular glass type in the optical industry due to its excellent optical properties. The inner and outer radii of the lens are 0mm, indicating a plano-concave shape.
This lens is coated with BBAR (Broadband Anti-Reflection) coating, designed for the wavelength range of 400-700nm. This coating reduces reflection and increases transmission, enhancing the lens performance in the specified wavelength range.
The coating on both the front and back surfaces is "hol bbbar 0 aoi", which is a specific coating type offered by Holmarc Opto-Mechatronics. This coating ensures high transmission and low reflection, making it suitable for various applications.