摘要
太赫兹(THz)光谱技术已被证明在有机及生物大分子检测领域具有巨大应用价值。然而,传统样品压片法在实际痕量待测物检测中无法应用,需要额外结构增强待测物与太赫兹波的相互作用。为了解决该问题,本文提出一种一维光子晶体(One-dimensional photonic crystals,1D-PCs)缺陷腔堆叠的太赫兹吸收谱增强结构。该结构采用多层金属平行平板波导分隔一系列缺陷腔宽度不同的一维光子晶体,并将样品薄膜涂敷在贯穿所有缺陷腔的衬底上。入射的宽带太赫兹波可同时激发不同层内光子晶体缺陷腔对应的多个不同频率的谐振峰,通过连接这些共振吸收峰组成包络得到增强的待测物太赫兹吸收光谱。仿真结果表明,0.1μm厚的α-乳糖样品在0.49~0.57 THz频段内可实现约303倍的吸收增强因子。该方法测量速度快,并且样品量用量小,为太赫兹吸收光谱应用于痕量分析物的高灵敏度检测提供了有效解决方案。
Terahertz(THz)spectroscopy technology has demonstrated great application value in the field of organic and biological macromolecule detection.However,the traditional sample pressing method cannot be applied in the actual detection of trace analytes,and additional structures are required to enhance the interaction between the analytes and THz waves.To solve this problem,we propose a terahertz absorption spectrum enhancement structure based on stacked one-dimensional photonic crystals(1D-PCs)defect cavities.The structure employs metal parallel-plate waveguides to separate a series of one-dimensional photonic crystals(1D-PCs)with defect cavities of varying widths,and coats the sample film on a substrate that penetrates all defect cavities.The incident broadband terahertz wave can simultaneously excite multiple resonant peaks at different frequencies corresponding to the photonic crystal defect modes in different layers.The enhanced terahertz absorption spectrum of the analyte can be obtained by linking the envelope formed by these reson-ant absorption peaks.The simulation results show that a 0.1μmα-lactose sample can accomplish an absorp-tion enhancement factor of approximately 303 times in the frequency range of 0.49 to 0.57 THz.This meth-od offers fast measurement speed and maintains a relatively low sample amount,providing an effective strategy for the enhancement detection of trace analytes by terahertz absorption spectrum.
作者
徐泽堃
李向军
严德贤
XU Ze-kun;LI Xiang-jun;YAN De-xian(College of Information Engineering,China Jiliang University of Technology,Hangzhou 310018,China)
基金
浙江省公益技术研究工业项目(No.LTGN23C180003)。
关键词
太赫兹波
堆叠
缺陷腔
一维光子晶体
增强吸收光谱
terahertz waves
stacking
defect cavity
one-dimensional photonic crystal
enhanced absorption spectrum
