衍射光栅教学中两种计算方法的比较

Comparison of Two Calculation Methods in Diffraction Grating Teaching

摘要: 光栅是波动光学的教学重点之一。对于衍射光栅，我们通常采用波矢法进行讲解，该方法具有易于计算和便于理解的优点，但是适用范围较窄，仅限于黑白光栅。相比而言，复数积分法讲解较少，该方法虽然适用范围广泛，但是不易于学生理解。本文主要比较这两种方法的特点，以及提出利用耦合模理论和傅里叶级数展开的办法来克服复数积分法在在教学中的缺点。

Abstract: Grating is one of the teaching emphases of wave optics. For diffraction gratings, we usually use the wave vector method to explain. This method is easy to calculate and understand, but its scope of application is narrow, and it is limited to black and white gratings. In contrast, the complex integral method is seldom explained. Although it is widely applicable, it is not easy for students to understand. This paper mainly compares the characteristics of these two methods, and proposes the method of using coupled mode theory and Fourier series expansion to overcome the shortcomings of complex integral method in teaching.