时域有限差分法模拟量子阱红外探测器光栅的光耦合

摘要

Diffraction grating is indispensable for quantum well infrared photodetectors(QWIP) in order to improve optical coupling because of the limitation of quantum selection rules. A numerical approach based on finite difference time domain(FDTD) method was presented for investigating the diffraction effect of a metal grating fabricated in QWIP. Simulation results demonstrate that such a complicated structure can be optimized by electromagnetic analysis based on the FDTD method. Detailed field distribution inside QWIP can be obtained for estimating the optical coupling efficiency of the grating.%由于量子选择定则的限制,对于量子阱红外探测器(QWIP),必须利用衍射光栅增强其光学耦合效率.本文给出了一种基于时域有限差分法(FDTD)的数值方法,计算制备在QWIP器件上的金属光栅的衍射效应.模拟计算的结果表明,FDTD方法是解析这种复杂结构内电磁场问题的有效手段.可以计算QWIP器件内各点电磁场所有分量的详细分布,进而可以估算衍射光栅的耦合效率,以及优化QWIP结构设计.