利用样品阱实现太赫兹超材料的超微量传感

Ultramicro-sensing of terahertz metamaterials implemented by using sample traps

提出了一种基于太赫兹(terahertz,THz)类电磁诱导透明(electromagnetically induced transpanrency like,EIT-like)效应的样品阱超材料传感器.传感器基础单元结构由一根金属线和一对开口谐振环(split ring resonators,SRRs)组成,二者耦合产生类EIT效应,在1.067 THz处得到一个半高全宽为178 GHz的透明峰,透明峰最大透过率为89.71%.其传感单位体积灵敏度为178 GHz/(RIU·mm^(3)),进一步分析该超材料谐振频点处的电场分布,发现两侧SRRs的开口处电场最强.我们设计构建样品阱仅在开口最强电场处,以光刻胶为待测物填入样品阱,并成功测得50 GHz频偏,验证样品阱结构可以运用于传感中.经研究分析,样品阱结构成功将样本量缩减至超微量级别,单位体积灵敏度提升至5538 GHz/(RIU·mm^(3)),提高了31倍.该样品阱成功实现对水、人皮肤和大鼠皮肤样本的鉴别,表明了构建样品阱在THz超材料超微量检测领域具有潜在的应用价值.

A metamaterial sensor implemented by using sample traps based on terahertz electromagnetically-induced-transparency-like(EIT-like)effect is proposed.The basic unit structure of the sensor is composed of a metal wire and a pair of split ring resonators(SRRs),which are coupled to produce EIT-like effect.The full width at half maximum of transparency peak is 178 GHz obtained at 1.067 THz,and the maximum transmittance of the transparency peak is 89.71%.The sensing characteristics of the structure are studied,and the sensitivity per unit volume is 178GHz/(RIU·mm^(3)).The analysis of electric field distribution at the resonant frequency point of the metamaterial indicates that the electric field at the gap of the SRRs on both sides is strongest.Sample traps are constructed at the gap where the electric field is strongest.The photoresist is filled into the sample traps as the object to be measured,and 50 GHz frequency offset is successfully measured,verifying that the sample trap structure can be applied to sensing.With samples placed in the sample traps,the sample volume is reduced to the ultra-micro level,and the sensitivity per unit volume is increased to 5538GHz/(RIU·mm^(3)),which is 31 times higher than original one.The successful identification of water,human skin and rat skin samples show that the metamaterial sensor implemented by using sample traps has potential applications in the field of ultra-micro detection.