Before revision: For example, GRIN lenses made from a radial gradient index material, such as SELFOC Microlens, have a refractive index that varies according to: , where nr is the refractive index at a distance, r, from the optical axis; no is the design index on the optical axis, and A is a positive constant .
After revision: For example, GRIN lenses made from a radial gradient index material, such as SELFOC Microlens, have a refractive index that varies according to: , where nr is the refractive index at a distance, r, from the optical axis; no is the design index on the optical axis, and A is a positive constant