The SLSQ-20-70N is a Plano-Concave Lens, a type of spherical lens, sourced from OptoSigma. This lens is uncoated and features a fused silica material (fused sil mal-1965) which is known for its excellent transparency and resistance to thermal shock. The lens has a base shape of a circle and a sub-type of Spherical Lens.
The lens has a diameter of 20.0 mm and a thickness at the edge of 3.6 mm. The center thickness is 2.0 mm. The effective focal length (EFL) is -70.0 mm, indicating that it is a diverging lens. The radius of curvature (R1) is -32.2 mm, and the back focal length (BFL) is -71.4 mm. The lens does not have any coating, which means it is in its raw state and users may need to apply their own coating depending on the application.
The lens is designed to work with a wavelength of 546.1 nm. It is important to note that the lens is uncoated, which means it may not perform optimally in environments with high humidity or where dust accumulation is a concern. However, uncoated lenses are often preferred in applications where cost and simplicity are prioritized.