Diffractive phase elements based on two-dimensional artificial dielectrics

We have designed, fabricated, and tested a blazed artificial dielectric transmission grating in fused quartz for use at the 633-nm wavelength. By locally varying the index, using fabricated two-dimensional arrays of dielectric cylinders, we can achieve a desired phase modulation to produce a diffractive phase element in one processing step. The effective index depends on the fill fraction of the cylinders.