• Material: UV Grade Fused Silica
• Wavelength Range: 185 nm - 2.1 μm

Thorlabs UV Grade Fused Silica Bi-Concave lenses are popular for many applications. Bi-Concave lenses have a negative focal length and are used to increase the divergence of a converging beam. Similar to a Plano-Concave lens, a Bi-Concave lens can diverge a collimated beam to a virtual focus as used in a Galilean type beam expander (see Drawing tab for reference).

Lens kits with bi-concave lenses made from BK7 are available.