基于四能级原子系统模型增益媒质激光原理研究

Analysis of lasing in gain medium based on four-energy level atomic model

作为超材料研究中的重点,增益媒质因其放大特性而表现出良好的应用前景.本文基于四能级原子结构系统模型,引入一种全新的抽运机理:高斯抽运.用时域有限差分方法对增益媒质激光产生原理进行模拟计算.数值模拟结果表明,该模型和新抽运机理的频谱特性、阈值特性以及动态演化过程和理论分析一致.研究结果可为计算更复杂超材料系统提供参考.

With the present interest in metamaterial, gain medium shows promise for complex system due to their amplification effect and wide potential application area. In this paper we present a model that simulates lasing in gain medium by using a model of four-energy level atomic system based on the finite-difference time-domain method.Meanwhile we propose a new pump mechanism, i.e., Gaussian Pump. It is found that results of the spectra, lasing threshold and population dynamics of the new pump mechanism are in good agreement with theoretical results. The results can also provide reference for caculating more complex metamateriai system.