基于可拉伸反射基底介质超光栅的太赫兹增强吸收谱  

Boosted Terahertz Absorption Spectrum by the Stretchable Reflective Substrate with a Dielectric Metagrating

作　　者：聂禄 李向军 王梓灏 孙文骁 孙杰[3] NIE Lu;LI Xiangjun;WANG Zihao;SUN Wenxiao;SUN Jie(Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province,China Jiliang University,Hangzhou 310018,China;Centre for THz Research,China Jiliang University,Hangzhou 310018,China;Zhejiang Institute of Metrology,Institute of Information and Electromagnetic Metrology,Hangzhou 310018,China)

机构地区：[1]中国计量大学信息工程学院浙江省电磁波信息技术与计量检测重点实验室,杭州310018 [2]中国计量大学信息工程学院太赫兹研究所,杭州310018 [3]浙江省计量科学研究院,信息与电磁计量研究所,杭州310018

出　　处：《光子学报》2024年第9期81-92,共12页Acta Photonica Sinica

基　　金：浙江省基础公益研究计划(No.LTGN23C180003);国家重点研发计划(No.2021YFF0600300)。

摘　　要：提出了一种利用纳米银浆作为反射层的可拉伸介质超光栅的亚波长增强结构,在指纹谱检测时可以有效提升待测物周围的局域场而实现超宽带太赫兹吸收谱信号增强。当太赫兹波以一定角度照射到可拉伸弹性衬底介质超光栅上表面时,对衬底进行一系列拉伸,不同的拉伸因子激发出一系列导模共振,对应的介质超光栅响应曲线上的谐振峰频率覆盖0.46~0.61 THz。选择0.2~1.0μmα-乳糖薄膜作为待测微量分析物时,各拉伸因子对应的谐振峰幅度随待测物的吸收谱大幅度改变,其包络线组成的吸收谱峰值比没有介质超光栅周期结构时,最多增强111倍。该基于金属基底的可拉伸微结构为微量分析物的太赫兹高灵敏度检测提供了一种新的有效方法。Although terahertz(THz)spectroscopy exhibits great application prospects in the fields of biomedicine and security detection,conventional sensing schemes face unavoidable limitations in the analysis of trace-amount samples.In this paper,a terahertz absorption spectrum boosting method based on the two-dimensional stretchable metagrating structures is proposed to improve the interaction between the terahertz wave and the trace-amount samples.Based on Guided-mode Resonance(GMR)effect,the local electric field in a thin-film sample can be enhanced by simultaneously varying the periodic length P of PDMS substrate and nano-Ag reflective layer,so that wideband terahertz absorption spectra can be greatly enhanced.This strategies for utilizing reflective layers exhibits a great absorption enhancement factor,of about 111 times,in a wideband terahertz frequency range,facilitating the identification of different trace-amount analytes,such as thinα-lactose films.The proposed method provides a new,to the best of our knowledge,choice for the enhancement of ultra-wide terahertz absorption spectra,and paves the way for the detection of trace-amount chemical,biomedical,or organic materials in the terahertz regime.Terahertz absorption spectroscopy enables many new potential applications,and demonstrates great promise in molecular fingerprint detection.THz detection is nondestructive,and many complex molecules have feature absorption resonance peaks in the THz spectral frequency range;according to molecular rotational and vibrational modes.However,traditional detection modes for identifying the fingerprint spectrum of trace-amount samples usually use more sample materials because of the diffraction of the THz.The response between waves and matter is also very weak.In order to improve the detection capability of trace-amount analytes,an effective strengthening strategy is to introduce additional resonance micro-structures to enhance the interaction between waves and matter.In this study,we introduce a two-dimensional stretchable meta

关 键 词：太赫兹波 指纹谱 动态拉伸 介质超光栅 纳米银反射 

分 类 号：TN214[电子电信—物理电子学]