中文摘要：

光通过透明平板介质时会在其上下表面发生反射和折射现象。光的本质是电磁波，由于电磁波是横波，所以光具有偏振的特性，研究偏振光传播过程中振幅和强度的变化对分析偏振态的改变具有重要意义。以最简单的偏振光——线偏振光为例，利用菲涅耳公式对线偏振光入射透明平板介质后振幅和强度的变化进行了讨论。

英文摘要：

Reflection and refraction phenomenon take place at the top and bottom surfaces of the transparent plate when light cros- ses through it. Light is the electromagnetic wave essentially, which is transverse wave, so the light has polarization characteristic. The discussions on the changes of amplitude and strength in the propagation of polarized light play an important role in the analy sis of the change of polarization state. In this paper, as the simplest example, the changes of amplitude and strength of the linearly polarized light are discussed in detail by using the Fresnel formula.