Application of an approximate vectorial diffraction model to analysing diffractive micro-optical elements

Scalar diffraction theory, although simple and efficient, is too rough for analyzing diffractive micro-optical elements. Rigorous vectorial diffraction theory requires extensive numerical efforts,and is not a convenient design tool. In this paper we employ a simple approximate vectorial diffraction model which combines the principle of the scalar diffraction theory with an approximate local field model to analyze the diffraction of optical waves by some typical two-dimensional diffractive micro-optical elements. Both the TE and TM polarization modes are considered. We have found that the approximate vectorial diffraction model can agree much better with the rigorous electromagnetic simulation results than the scalar diffraction theory for these micro-optical elements.