复合周期双层金属膜光栅的多特性融合研究  

Multi-Characteristic Integration of Double-Layer Metal Film Grating with Composite Periodic Structure

作　　者：崔文丽[1] 彭伟[2] Cui Wenli;Peng Wei(School of Science,North University of China,Taiyuan,Shanxi 030051,China;School of Physics,Dalian University of Technology,Dalian,Liaoning 116024,China)

机构地区：[1]中北大学理学院,山西太原030051 [2]大连理工大学物理学院,辽宁大连116024

出　　处：《光学学报》2022年第8期234-240,共7页Acta Optica Sinica

基　　金：山西省青年科技研究基金项目(201901D211230)。

摘　　要：设计了一种性能优异的多频带、多特性融合的复合周期双层金属膜纳米光栅结构。通过运用有限元法进行仿真,发现该结构在65°底部TM模式偏振光斜入射下,能够在波长760、904、1028、1216 nm处出现高吸收,其吸收强度分别为98.73%、92.84%、97.57%、99.11%。进一步模拟发现,多频带吸收峰还兼具窄带偏振滤波以及折射率传感特性,其最大折射率灵敏度为2080 nm/RIU,最大品质因数为92.1 RIU^(-1)。另外,通过周期调制,该结构还实现了在近红外波段从944~1206 nm宽波段范围的窄带偏振滤波可调谐功能。通过对电磁场、表面电流、表面电荷的分布分析,给出了该结构多频带、多特性融合的物理激发机制。该复合周期双层金属膜光栅结构在微型化与高度集成化的多光谱红外探测、光谱成像以及生物传感等领域具有广阔的应用前景。A double-layer metal film grating with a composite periodic structure is designed,which features multiple frequency bands,multi-characteristic integration.The simulation by a finite element method,and we find that this structure can achieve high absorption at resonant wavelengths of 760,904,1028,and 1216 nm under transverse-magnetic(TM)polarized illumination on the bottom of the nanograting at an incident angle of 65°.Its absorptivity can be up to 98.73%,92.84%,97.57%,and 99.11%,respectively.Further simulation reveals that multiband absorption peaks also possess the characteristics of narrowband polarization filtering and refractive index sensing.Its maximum refractive index sensitivity is 2080 nm/RIU and the maximum figure of merit(FOM)is 92.1 RIU^(-1).In addition,period modulation enables the tunability of narrowband polarization filtering in a wide near-infrared wavelength range from 944 nm to 1206 nm.We explore the underlying integration mechanism by analyzing the distributions of the surface electromagnetic field,surface current,and surface electric charges.The results show that the designed double-layer metal film grating with a composite periodic structure has a broad application perspective in miniaturized and highly integrated multispectral infrared detection,spectral imaging,and biosensing.

关 键 词：光学器件 表面等离激元 微纳光栅 多特性融合 

分 类 号：O436.3[机械工程—光学工程]