采用有限时域差分(FDTD)法和传输矩阵法(TMM)计算了一维光子晶体微腔中模式的阈值和模场的空间分布,并用局域化长度和模面积描述了其空间分布特性.着重研究了模场的空间分布对阈值特性的影响.模拟结果显示,激光器的阈值依赖于模式的空间分布,局域化长度和模面积最小的模式具有最低阈值.通过调节包括缺陷宽度、光学厚度比、折射率比等介质参量,可以有效地调节模式的局域化长度和模面积,从而降低激光器的阈值.
The spatial profile and its influence on the lasing threshold of defect modes are investigated by use of the finite-difference time-domain (FDTD) method and the transfer matrix method (TMM) in a one-dimensional photonic crystal through the two effective parameters, the localization length and the mode area. The results indicate that the lasing threshold becomes lower if the localization length and mode area get smaller. The localization length and the mode area of defect modes can be effectively modified to decrease the lasing threshold by adjusting parameters such as the defect width, the ratio of optical thickness and the ratio of refractive index.