This is a Plano-Concave Spherical Lens, type HO-PVL50-03B, 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 -150mm, making it a negative or diverging lens.
The lens is made of N-BK7, a popular optical glass from Schott, known for its excellent optical properties. The lens's inner and outer radii are both zero, 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's performance in the specified wavelength range.
The lens's coating on both the front and back surfaces is "hol bbbar 0 aoi", indicating a broadband anti-reflection coating with a 0-degree angle of incidence. This coating is designed to minimize reflection and maximize transmission, ensuring optimal performance.