Plano-concave lens, Fused silica, Ø 22.4 mm, f = -50 mm, ARB2-NIR

Plano-concave singlet in Fused silica, Ø 22.4 mm, focal length -50 mm. ARB2-NIR broadband AR coating. Negative focal length: diverges the beam, for beam expanders and to shorten system length.