DESIGN STRATEGY OF DIFFRACTIVE ELEMENTS WITH PRESCRIBED DIFFRACTION ANGLES IN NON-PARAXIAL REGION

Diffractive elements designed on the basis of scalar diffraction theory are confined to paraxial optical functions. The reason is the limited range of validity of scalar theory. To overcome this restriction, the design must be performed using rigorous electromagnetic theory, which is able to handle arbitrary feature sizes. However, the optimization concepts for the design of diffractive elements in the paraxial domain fail, when they are applied to rigorous design in the non-paraxial domain. The reason for this failure is discussed and a modified strategy is presented to design diffractive elements in the non-paraxial domain. Multiple beam splitters with prescribed diffraction angles are synthesized.