Plano Concave Lens

Plano-concave lenses are used for beam expansion.A beam of parallel light is concerted into a diverging light, and the diverging light is reversely focused on the virtual focal point of the flat concave lens. The focal length is negative, and one side is flat, another side is concave.

A plano concave lens emits a collimated beam from a virtual focus, usually used in a Galilean beam expander.

Ruike Optics manufacture plano concave lens with material BK7, Fused Silica,CaF₂, Sapphire, Silicon, Germanium with AR Coating.

How to calculate Focal length of PCV?

F=R/(n-1)     

F is the focal length of the lens

n is the refractive index of the lens

R is the curvature radius of the lens 

The Common glass Refractive index 

Parameter of Plano Concave Lens

Material:BK7 Fused Silica CaF₂ MgF₂ Sapphire Germanium Silicon ZnSe ZnS.

Diameter:0.5-600mm

Dia Tolerance:+/-0.02mm

Thickness Tolerance:+/-0.01mm

Centeration<30 arcmin

Flatness<1/20 lambda

Surface Quality:10-5

Coating: AR BBAR HR.