Patent ID: 8077390

Claim:
A method of producing an optical element that has a desired fixed spatial variation in refractive index, the method comprising: providing a curable liquid crystal composition; applying a substantially uniform electric field to the liquid crystal composition to induce a desired refractive index; curing a portion of the liquid crystal composition, while the electric field is still applied, to fix the refractive index of that portion when the electric field is removed; and repeating the applying and curing steps, curing different portions of the liquid crystal composition each time, to cure the entire liquid crystal composition to form the optical element having the desired fixed spatial variation in refractive index, wherein the applied electric field is adjusted prior to each curing step, and wherein the curable liquid crystal composition is provided in a form of a lamella defining a plane, and the different portions of the liquid crystal composition cured each time are displaced from each other in the plane of the lamella, to provide spatial variation in refractive index over the plane of the lamella.