基于三维开口谐振环阵列和微流通道的太赫兹超材料吸收体传感器

Terahertz Metamaterial Absorber Sensor Based on Three-Dimensional Split-Ring Resonator Array and Microfluidic Channel

基于三维开口谐振环(SRR)阵列和微流通道,在太赫兹频段内实现了一款基于超材料吸波器的高灵敏度折射率传感器,三维SRR阵列完全浸没于微流通道内,注入微流通道内的液相分析物在作为被测分析物的同时还充当了超材料吸波器的中间介质层。当微流通道的高度固定为33.1μm,而注入微流通道内的液相分析物的折射率从1.0变化到1.8时,该太赫兹超材料吸波器可作为折射率传感器,对应的折射率频率灵敏度达到379GHz/RIU。仿真结果表明,该太赫兹超材料吸收体传感器的谐振电磁场被扩展到三维空间,并在微流通道内得到了很大程度的集中和增强,从而实现了谐振电磁场与待测分析物的空间重叠,增强了谐振电磁场与被测分析物之间的相互作用,进而实现了对液相分析物的高灵敏度传感。同样基于CST MicrowaveStudio仿真软件仿真研究了微流通道的高度和顶层覆盖电介质的厚度对超材料吸收体传感器的折射率灵敏度的影响。通过选择合适的微流通道高度和覆盖电介质厚度可获得更高的折射率灵敏度。总之,基于三维SRR阵列和微流通道的太赫兹超材料吸收体传感器具有更高的品质因数和折射率频率灵敏度,在无标记的快速生物医学传感中具有潜在的应用。

Based on the three-dimensional(3D)split-ring resonator(SRR)array and microfluidic channel,a high-sensitivity refractive index sensor based on a metamaterial(MM)absorber is realized in the terahertz(THz)band.The 3D SRR array is completely immersed in the microfluidic channel.The liquid-phase analyte in the microfluidic channel serves as the intermediate layer of the MM absorber while serving as the analyte to be measured.When the height of the microfluidic channel is fixed at 33.1μm and the refractive index of the liquid-phase analyte injected into the microfluidic channel changes from 1.0 to 1.8,the THz MM absorber can be used as a refractive index sensor,and the refractive index frequency sensitivity reaches 379 GHz/RIU.Simulation results show that the resonant electromagnetic(EM)field of the THz MM absorber sensor is extended to 3D space,and is greatly concentrated and enhanced in the microfluidic channel,thereby realizing the spatial overlap of the resonant EM field and the analyte to be measured.The interaction between the resonant EM field and the measured analyte is enhanced,and thus the high-sensitivity sensing of liquid analytes is achieved.The influences of the height of the microfluidic channel and the thickness of the top-layer covering dielectric on the refractive index sensitivity of the MM absorber sensor are also studied based on CST Microwave Studio simulation software.In short,the THz MM absorber sensor based on the 3D SRR array and microfluidic channel has a higher quality factor and refractive index frequency sensitivity,and has potential applications in label-free fast biomedical sensing.