SLB-20B-25N 20.0 mm Dia. x -24.7 mm FL; Double-Concave Lens Uncoated

The SLB-20B-25N is a high-quality double-concave lens offered by OptoSigma, a leading vendor in the optical industry. This lens, designed for use in a wide range of optical applications, boasts a diameter of 20.0 mm and a focal length of -24.7 mm, making it a versatile choice for many setups.

The lens is made from n-BK7 Schott, a popular material in the optical industry due to its excellent optical properties. This material ensures high transmittance and low dispersion, making it ideal for applications that require high image quality and color fidelity.

The geometry of the lens is characterized by its concave-concave shape, with a thickness of 6 mm at the edge and 2 mm at the center. The inner and outer radii are 0, indicating a circular base shape. The effective focal length (EFL) is -24.7 mm, and the back focal length (BFL) is -25.3 mm.

Notably, this lens is uncoated, which means it does not have any anti-reflective or other coatings applied to its surfaces. While this may result in a higher level of reflection at the air-glass interfaces, it can also make the lens more cost-effective and suitable for applications where such coatings are not necessary.

The lens is currently in stock and can be purchased directly from the OptoSigma website, with the provided weblink offering a direct path to its product page.