AI 中文总结
该研究理论分析三维金刚石光子带隙晶体掺杂替位缺陷后的缺陷态，结合耦合偶极子法数值模拟，明确缺陷态的存在条件、本征频率与寿命随晶体尺寸的变化规律，还发现带隙外的失谐解耦态。
AI 中文摘要
我们对由点散射体构成并掺杂有替位缺陷的三维金刚石晶体的光子带隙内的缺陷态开展理论研究。这些缺陷会在光子带隙内引入局域态，其存在条件与本征频率可通过无缺陷理想晶体的格点格林函数来表达；非格点格林函数也被作为距离的函数进行计算，结果显示其在约2个原胞范围内消失。通过将无限晶体极限下的结果与基于耦合偶极子法的数值模拟结果进行对比，我们分析了有限尺寸效应。数值模拟不仅再现了带隙内缺陷态的本征频率，还给出了源于晶体有限尺寸的缺陷态寿命；缺陷态的寿命随晶体尺寸呈指数增长，大尺寸晶体的缺陷态寿命极长。除三维光子带隙内的缺陷态外，这些缺陷还会在带隙外产生与理想无缺陷晶体频谱强失谐的态，这类态与理想晶体频谱解耦。
英文摘要
We perform a theoretical study of defect states within the photonic band gap of three-dimensional diamond crystals composed of point scatterers and doped with substitutional defects. The defects introduce localized states inside the photonic band gap, whose existence conditions and eigenfrequencies are expressed in terms of the on-site Green's function of the ideal defect-free crystal. Off-site Green's functions are also calculated as function of distance and are shown to vanish within approximately two unit cells. Finite-size effects are analyzed by comparing the results obtained in the infinite-crystal limit with numerical simulations based on the coupled-dipole method. The latter not only reproduce the eigenfrequencies of the defect states within the band gap, but also provide their lifetimes originating from the finite crystal size. The lifetimes of the defect states increase exponentially with crystal size, becoming very long for large crystals. In addition to defect states in the three-dimensional photonic band gap, the defects also give rise to strongly detuned states outside the gap, which decouple from the spectrum of the ideal defect-free crystal.
Comments15 pages, 11 figures
