This is a PLCC-25.4-257.5-C laser grade plano-concave lens, sourced from CVI Laser Optics. The lens has a diameter of 25.4 mm and a center thickness of 3.9 mm. The effective focal length (EFL) of this lens is -500mm, making it a concave lens. The radius of curvature for this lens is -257.5 mm.
The lens is made of N-BK7 Schott glass, a popular material for optical elements due to its excellent optical properties and wide transmission range. This lens is uncoated, meaning it does not have any additional layers to enhance its optical properties or protect it from environmental factors.
The lens is designed for use with a wavelength of 588 nm. It is a spherical lens, which means it has the same curvature in all planes. The lens is circular in shape, making it suitable for a wide range of applications.
The lens is in stock and available for immediate purchase. More detailed information about this lens, including its full specifications, can be found in the linked PDF document from CVI Laser Optics.