缺陷对对称结构光子晶体透射谱的影响

摘要

The influence of defect on the transmission spectrum of symmetrical structural photonic crystal is studied by the theoretical transmission matrix and numerical simulation method. The result shows that the transmis-sion properties of photonic crystals are very sensitive to the response of the lattice constant of the medium. When there is no defect in the symmetrical structural photonic crystal, a strip of defect mode appear in the center of for-bidden band of the photonic crystal, and the bandwidth of the defect mode become narrow with the increase of the periodicity of element medium permutation;when the symcenter of symmetrical structural photonic crystal is insert-ed a single defect, narrow defect mode will not appear in the forbidden band center, which means the transmission spectrum is similar to that of standard period symmetrical structural photonic crystal;when the two ends of photonic crystal are inserted symmetrical two-layer defect, defect mode appears in the forbidden band center, but its band-width is wider than that of defect mode of photonic crystal without defect;when the internal sides of element medi-um permutation period are inserted symmetrical two-layer defect, three narrow defect modes appear in the forbid-den band, and with the increase of the distance between the two layers of defect, the defect modes draw close to the forbidden band center forming a degenerate trend;when the internal sides of element medium are inserted symmet-rical two-layer defect, several narrow defect modes appear in the forbidden band, and the numbers of the defect modes may be adjusted by the periodicity of element medium permutation. The modulation of defect on the trans-mission spectrum of symmetrical structural photonic crystal can provide reference for photonic crystal to make de-vices like multichannel optics filters and optical switches, and so on.%利用传输矩阵法理论，研究缺陷对对称结构光子晶体透射谱的影响规律，结果表明：当对称结构光子晶体中无缺陷时，光子晶体禁带中心出现一条缺陷模，且缺陷模的带宽随基元介质排列周期数增大而变窄；当对称结构光子晶体的对称中心插入单一缺陷时，禁带中不出现窄缺陷模，即透射谱与标准周期结构光子晶体的透射谱相似；当光子晶体的两端插入对称的两层缺陷时，禁带中心出现缺陷模，但缺陷模的带宽宽于无缺陷时光子晶体的缺陷模带宽；当光子晶体的内两侧基元介质排列周期之间插入对称的两层缺陷时，禁带中出现三条窄缺陷模，且随着两缺陷之间距离增大，缺陷模向禁带中心靠拢形成简并的趋势；当光子晶体的内两侧基元介质之间插入对称的两层缺陷时，禁带中出现多条窄缺陷模，且缺陷模的条数可由含缺陷单元介质排列周期数调节。缺陷对对称结构光子晶体透射谱的调制规律，为光子晶体制备多通道光学滤波器、光学开关等器件提供参考。