一种计算和分析二维光子晶体缺陷模式的方法

通过改进时域有限差分(FDTD)法,计算和分析了二维光子晶体的缺陷模式。运用一维时域有限差分算法和线性插值法在总场散射场(TF-SF)连接边界引入入射平面波,采用完全匹配层(PML)技术对外行波进行了有效吸收。计算和分析结果表明,在光子晶体非对称方向入射的平面波能激发所有的缺陷模式,选取合适的探测点位置收集电场值,经快速傅里叶变换(FFT)能得到所有的共振峰值。另外,采用该方法研究了二维正方介质柱光子晶体缺陷模的共振频率与缺陷介质柱半径和介电常量之间的关系。结果表明通过改变缺陷的半径和介电常量大小可以在光子晶体禁带中一定的范围内调节缺陷模式的共振频率大小。

A Numerical Method to Calculate and Analyze of Defect Modes in Two-Dimensional Photonic Crystal

A numerical method based on the modified finite-difference time-domain(FDTD) method for calculating and analyzing defect modes in a two-dimensional photonic crystal is presented.An ideal plane wave incident at different angles is realized by using the auxiliary one-dimensional FDTD method and linear interpolation at the total field-scattered field interface.Perfect matched layer technique is employed to absorb the out going wave efficiently.Numerical simulations show that all defect modes can be excited by an incident plane wave along a non-symmetric direction of the photonic crystal.The values of electric field are recorded by choosing a suitable detector position,and all resonant frequencies can be obtained by fast Fourier transform.The relationship between the resonant frequency in a two-dimensional square photonic crystal consisting of dielectric rods and the radius and dielectric constant of the rods is also investigated.The numerical results show that the value of the resonant modes of the photonic crystal can be modulated by changing the radius and dielectric constant.