87-993 50mm Dia. Germanium Infrared Aspheric Lens; EFL=25mm; NA=1 Uncoated

This is the 87-993 model from Edmund Optics, a 50mm diameter Germanium Infrared Aspheric Lens with an effective focal length (EFL) of 25mm and a numerical aperture (NA) of 1. The lens is uncoated, offering a unique set of properties suitable for specific applications.

The lens is designed in an aspheric shape, which is a type of lens where one or both surfaces have a non-spherical shape. This design helps to reduce spherical aberration and other optical aberrations, providing sharper images and a wider field of view compared to traditional spherical lenses. The base shape of the lens is circular, ensuring uniform light distribution and reducing vignetting effects.

The lens is made of germanium, a material known for its excellent transmission properties in the infrared region of the spectrum. The germanium burnett material used in this lens ensures high-quality performance in the 4000nm wavelength range.

The geometry of the lens includes an inner radius of 0, an outer radius of 0, a diameter of 50mm, a thickness at the edge of 2.5mm, and a thickness at the center of 7.75mm. The lens has an EFL of 25mm, a back focal length (BFL) of 20.64mm, and a numerical aperture (NA) of 1. The aspheric coefficients (k1 and k2) are 0, indicating a high degree of symmetry and precision in the lens design.

The lens does not have any coating, which can affect its performance in certain applications. However, the uncoated design can be beneficial in specific use cases where anti-reflection coatings are not required or desirable.