The SLB-20B-20NIR1 is a high-quality double-concave lens, designed and manufactured by OptoSigma. This lens, with a diameter of 20.0 mm, is specifically engineered for use within the wavelength range of 633-1064nm, making it suitable for a variety of applications in the optical spectrum.
The lens is constructed from n-bk7 Schott, a popular material in the optical industry due to its excellent optical properties. The base shape of the lens is circular, and it features a double-concave geometry, with radii of curvature of r1=-20.76mm and r2=20.76mm. This geometry results in a back focal length (BFL) of -20.3mm and an effective focal length (EFL) of -19.7mm.
The lens has a center thickness of 2mm and an edge thickness of 7.1mm, providing robustness and durability. The lens is coated with Opt IR1 on both the front and back surfaces, enhancing its performance within the specified wavelength range.