68-251 25mm Dia. Germanium Infrared Aspheric Lens; EFL=12.5mm; NA=1 BBAR 8-12µm

This is a high-quality 25mm diameter germanium aspheric lens, designed for use in the infrared spectrum with a wavelength of 4000nm. The lens is sourced from the renowned optical vendor, Edmund Optics, and is available for purchase through their online catalog.

The lens features an effective focal length (EFL) of 12.5mm, providing a compact and efficient optical solution. It boasts a high numerical aperture (NA) of 1, indicating a wide acceptance angle and excellent light-gathering capabilities. The aspheric design of the lens helps to reduce spherical aberration, providing sharper images and improved performance over traditional spherical lenses.

The lens is made from germanium, a material known for its excellent transmission properties in the infrared spectrum. It is coated with Edmund Optics' proprietary BBAR (Broadband Anti-Reflection) coating, which is specifically designed for the 8-12µm range. This coating helps to reduce surface reflections, improving transmission and enhancing overall performance.

The lens has a thickness of 2.5mm at the edge and 4.24mm at the center, providing structural rigidity and resistance to deformation. The front and back surfaces of the lens are coated with the same AR coating, ensuring optimal performance from both sides.

In terms of geometry, the lens has an inner radius of 0mm, an outer radius of 0mm, and a diameter of 25mm. The front and back faces are defined by the radii r1=41.397mm and r2=435.187mm, respectively. The back focal length (BFL) is 11.61mm.

This lens is a versatile and high-performing option for any application that requires a high-quality infrared lens. It is available for purchase directly from Edmund Optics, and the link to the product page is provided in the item data.