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Fresnel surface

The Fresnel surface is experimental.

The Fresnel surface is used to model the effect of an axially symmetric Fresnel lens. The surface is planar, in the sense that the rays are propagated until they hit the plane of the surface. But the rays are refracted assuming a surface slope given by the sag expression of an asphere surface.

This surface does not model the actual groove structure of a real Fresnel lens. It merely accounts for the deflection of rays in an idealized picture in which the groove structure is very fine.

Parameters

a2, a4,..., a20
Aspheric coefficients used to determine surface slope

See also