MULTILAYER TECHNOLOGY FOR DIFFRACTIVE OPTICAL-ELEMENTS

The proposed multilayer technology makes it possible to approximate a continuous phase distribution by discrete phase steps. Compared with b inary techniques, a higher diffraction efficiency can be achieved. In most known processes a bulk substrate is used and etched directly; the refore it is difficult to control the height of the phase steps. We pr opose applying layers of a well-known thickness and structuring them w ith a selective etching process. In this new multilayer process for re flecting elements a system of metal and dielectric layers is used that can easily be produced by standard methods. (C) 1996 Optical Society of America