This is a high-quality 12.5mm diameter germanium aspheric lens, designed for use in the infrared spectrum with a wavelength of 8000nm. The lens is sourced from the reputable vendor, Edmund Optics, and is available for purchase through their website. The catalog number for this lens is 22-778.
The lens features a focal length of 37.5mm and a numerical aperture of 0.16. It is made from germanium burnett, a material well-suited for infrared applications due to its high refractive index and transparency in the infrared spectrum. The lens has a double-sided broadband anti-reflection coating, specifically designed for the 3-12µm range, which reduces surface reflections and increases transmission.
The lens's geometry includes an inner radius of 0mm, an outer radius of 0mm, a thickness at the edge of 2.83mm, and a thickness at the center of 3mm. The front and back surfaces of the lens are aspheric, with the front surface having a radius of curvature of 112.753mm and the back surface being planar. The lens also has a front surface sag of -0.9mm and a back surface sag of 0mm.