众所周知,具有二元结构的衍射光栅的衍射效率按标量衍射理论约为40％。本文根据耦合波理论叙述利用小于波长的结构能提高衍射效率的情况。图1示出本文提出的衍 It is well known that the diffraction efficiency of a diffraction grating having a binary structure is about 40% based on scalar diffraction theory. This paper describes the use of less than the wavelength of the structure can improve the diffraction efficiency based on the coupled wave theory. Figure 1 shows the derivative proposed herein