68-245 25mm Dia. Germanium Infrared Aspheric Lens; EFL=20mm; NA=0.63 BBAR 3-5µm

This is the 68-245 model from Edmund Optics, a 25mm diameter Germanium Aspheric Lens designed for infrared applications with a wavelength of 4000nm. The lens boasts an effective focal length of 20mm and a numerical aperture of 0.63, making it a high-performance component in its class.

The lens is made of Germanium burnett, a material known for its excellent transmission properties in the infrared spectrum. It features a Base Shape of Circular, with an Inner Radius and Outer Radius of 0, indicating a uniform thickness. The lens has a thickness edge of 2.5mm and a center thickness of 3.7mm, providing structural rigidity and stability.

The lens's geometry includes a front surface with a radius of curvature (R1) of 60.5mm and a back surface (R2) of 0mm, suggesting a highly curved front surface for optimal light focusing. The back focal length (BFL) is 19.08mm, and the lens has a high refractive power due to its short focal length and large diameter.

The lens is coated with edm arcedgermanium35 on both the front and back surfaces, providing broadband anti-reflection (BBAR) properties in the 3-5µm range. This coating reduces surface reflections, improving transmission and overall optical performance.

The lens's shape is Aspheric, which means it has a non-spherical surface to correct optical aberrations, providing superior image quality over a wider field of view compared to traditional spherical lenses. This makes the 68-245 an ideal choice for applications requiring high resolution and low distortion, such as infrared imaging, spectroscopy, and beam shaping.