Materials with a desired refraction coefficient can be made by embedding small particles

A method is proposed to create materials with a desired refraction coefficient, possibly negative one. The method consists of embedding into a given material small particles. Given n0(x), the refraction coefficient of the original material in a bounded domain D⊂R3, and a desired refraction coefficient n(x), one calculates the number N(x) of small particles, to be embedded in D around a point x∈D per unit volume of D, in order that the resulting new material has refraction coefficient n(x).