基於嚴格耦合波理論對繞射光柵之向量繞射理論分析

Abstract

一維週期的光柵是最基本而簡單的繞射光學元件，已被廣泛地使用在積體光學、全像光學、光電子學以及光譜學等領域。在光學元件的設計與應用時，效率是其中最重要的考慮因素。傳統的標量繞射理論在光柵週期與入射光波長相近時，已無法精確地分析預測繞射效率的分布，所以我們以向量繞射理論之嚴格耦合波理論為基礎，發展光柵模擬程式，此模擬程式適用於任意有週期性表面輪廓之繞射光柵。利用完成的程式分別模擬光柵參數與環境參數對一維二階光柵繞射效率的影響，並利用超大型積體電路的製作技術與準分子雷射直寫等方式製作光柵。量測其繞射效率分布，結果與理論計算有些許出入，我們也將討論其偏差原因。

One dimension periodic grating is the most basic and simple element of diffraction optics. It has many applications in integrated optics, holography, electronic optics, and spectroscopy. In its design and applications, diffraction efficiency is one of the most important factors. When the period of grating is near the wavelength of incidence light, conventional scalar diffraction theory is not available to analyze the distribution of diffraction efficiency. Therefore, based on the rigorous coupled-wave theory, we developed a simulation program of vector diffraction analysis for modeling any type of surface-relief grating. With the simulation program, we analyzed the effect of grating's parameters and of surroundings' factor on diffraction efficiency. We fabricated the gratings of binary surface-relief by VLSI techniques and laser direction writing techniques. We found that the measured results of these elements were some different from the results calculated with the simulation program. We discussed the reasons of the differences.