68-240 25mm Dia. Germanium Infrared Aspheric Lens; EFL=40mm; NA=0.31 Uncoated

The 68-240 is a 25mm diameter germanium aspheric lens, offering an effective focal length (EFL) of 40mm and a numerical aperture (NA) of 0.31. This lens is sourced from Edmund Optics and is uncoated.

The lens's geometry is intricately designed, with an inner radius of 0mm, an outer radius of 0mm, and a thickness at the edge of 2.38mm. The EFL of 40mm is complemented by a back focal length (BFL) of 37.89mm, providing a balanced optical path. The lens's shape is aspheric, featuring a first radius (R1) of 44.05mm and a second radius (R2) of 65.6mm.

The lens's material is germanium, a common choice for infrared (IR) applications due to its high refractive index and transparency in the IR spectrum. The lens is uncoated, which means it does not have any additional layers to enhance its optical properties. However, uncoated lenses can be advantageous in certain applications where specific coatings may interfere with the desired optical performance.

This lens is a part of Edmund Optics' extensive catalog, and the provided weblink leads directly to the product page for easy access and further information. The lens's catalog number is 68-240, making it easy to identify and cross-reference with other vendors or documentation.