利用马吕斯定律，通过自建实验平台精确研究了GaN 基半导体激光器的偏振特性.实验结果表明:激射阈值之后 (30 mA 以上)，GaN 基半导体激光器的发光具有较高的偏振度，其偏振度接近于1;远低于阈值的5 mA 处，其偏振度接近于0. 70，在阈值前的27 mA 处，其偏振度已经接近0.93.这表明在远低于激射阈值的电流区间，GaN 基半导体激光器的发光中不仅 存在不具有偏振度的自发辐射发光，而且还存在具有和阈值后同偏振方向的线偏振光，且线偏振光的占比较大.

Based on Marius’s law in the“Physics of University Physics”，the polarization characteristics of GaN-based semiconductor lasers are studied accurately by self-built experimental platform. The experimental results show that after the lasing threshold，the GaN-based semiconductor laser has a higher degree of polarization and it is close to 1. At 5 mA far below the lasing threshold the polarization degree is close to 0.70，and it is already close to 0.93 at 27 mA below the threshold. This shows that not only the spontaneous emission with no degree of polarization but also the linearly polarized light with the same polarization direction as the threshold exists in the light emission of the GaN-based semiconductor laser far below the lasing threshold，and the ratio of this linearly polarized light in the total light intensity is very high.