69-664 25mm Dia. x 40mm FL; Coated; Ge Plano-Convex Lens BBAR 8-12µm

The 69-664 is a 25mm diameter, 40mm focal length plano-convex lens, designed for use in the 8-12µm spectral range. This lens is sourced from Edmund Optics, a leading provider of optical components.

The lens is made from Germanium Burnett, a material known for its high refractive index and transparency in the infrared spectrum. The plano-convex geometry, where one side is flat and the other is curved, is ideal for applications that require a high level of focusing precision.

The lens features a broadband anti-reflection (BBAR) coating on both the front and back surfaces. This coating, identified as 'edm arcedgermanium81', is specifically designed to reduce surface reflections and increase transmission in the 8-12µm range. The coating also provides protection against environmental contaminants and wear, enhancing the lens's durability and longevity.

The lens has a center thickness of 3mm and an edge thickness of 2.35mm, providing a robust structure while maintaining a low profile. The inner and outer radii are 0mm, indicating a sharp transition between the lens and the surrounding medium.

The lens's effective focal length (EFL) is 40mm, a common choice for applications that require a moderate level of magnification. The back focal length (BFL) is 39.25mm, which should be considered when designing the optical system to ensure adequate clearance for other components.