69-862 12.5 mm Dia. N-SF5 Precision Aspheric Lens; EFL=9.5mm; NA=0.66 BBAR 600-1050nm

This is the 69-862 model from Edmund Optics, a high-precision 12.5 mm diameter Aspheric Lens made from N-SF5 Schott material. The lens boasts a 0.66 numerical aperture (NA) and an effective focal length (EFL) of 9.5mm, making it suitable for applications that require a high level of light gathering and focusing capability.

The lens features a broadband anti-reflection (BBAR) coating, optimized for the 600-1050nm wavelength range, which significantly reduces surface reflections and increases transmission. This coating enhances the lens' performance in near-infrared (NIR) applications, such as biomedical imaging, spectroscopy, and optical metrology.

The lens geometry is defined by its inner and outer radii, both of which are 0 in this case, indicating a symmetrical design. The lens has a thickness of 1.6mm at the edge and 5mm at the center. The front and back surfaces of the lens are aspheric, with the front surface having a radius of curvature (R1) of 6.391mm and the back surface being planar (R2=0). The back focal length (BFL) is 6.51mm.

The lens's shape is defined by its conic constant (k1) of -1.186336, which determines the degree of asphericity. The lens's design minimizes spherical aberration and other optical aberrations, providing superior image quality and high resolution.