Author(s)

Xuehui Xiong¹, Ping Lu²

¹School of Physics and Information Engineering, Jianghan University, Wuhan, China.
²School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China.

Rigorous Coupled-Wave Approach (RCWA) has been used successfully and accurately to study simple grating structures, such as one-layer gratings, one-whole gratings. In this paper, RCWA is expanded to solve Sandwich gratings (SG), which is composed of two identical planar dielectric gratings adjoined by thin metallic or dielectric film. The electromagnetic analytic expressions for each layer of SG structure are given and rigorous coupled-wave equations are deduced. The numerical investigations for the diffraction spectra of SG by our theoretical and computer programs are in good agreement with the results of classical RCWA in the condition when a Sandwish grating is simplified to a classical one-layer grating. The calculations by our programs of another condition when a Sandwish grating is degenerated to a classical single planar structure also conform to the results of classical electromagnetic theory. The research results above indicate that the extended theoretical formula has backwards compatibility and is self-consistent with the classical theory.

Rigorous Coupled-Wave Approach, Sandwich Gratings, Self-Consistent

Xiong, X. and Lu, P. (2016) Rigorous Coupled-Wave Approach for Sandwich Gratings. Journal of Applied Mathematics and Physics, 4, 1439-1445. doi: 10.4236/jamp.2016.48148.