13-506 50mm Dia. S-LAH64 NIR Aspheric Lens; EFL=40mm; NA=0.63 Uncoated

This is the 13-506 model from Edmund Optics, a 50mm diameter, uncoated NIR (Near-Infrared) Precision Aspheric Lens. The lens is designed for a wavelength of 780nm and has a high numerical aperture (NA) of 0.63, indicating a wide angle of acceptance for light rays, which is beneficial for imaging applications.

The lens geometry is defined by its inner and outer radii, both of which are 0 in this case, suggesting a simple, circular shape. The lens has a thickness of 4.9mm at the edge and 15.5mm at the center, with a 40mm effective focal length (EFL). The aspheric design, characterized by the coefficients k1 and k2, helps correct spherical aberration, a common issue in traditional spherical lenses.

The lens is made of S-LAH64 material from Ohara, a high-refractive index glass suitable for infrared applications. The uncoated surface may result in higher reflectivity, especially at larger incidence angles, but it can also reduce surface scatter and maintain high contrast in certain imaging scenarios.

Please note that the lens does not have any anti-reflective coating, which could be crucial for applications requiring high transmission and low reflectivity. However, its high NA, large diameter, and aspheric design make it a versatile choice for various imaging and light manipulation tasks in the near-infrared spectrum.