Study Of Metamaterial Absorber Based On Composite MIM Structure And Its Biosensing Application

Metamaterials,artificial composite structures with exotic material properties,have become a new field of science involving physics,materials science,engineering and chemistry since the beginning of the 21st century.MIM metamaterial absorber based on layered metal-insulator-metal,as a typical manifestation of metamaterial,has been applied not only in the research of light sources and detectors but also in the sensing and detection of gas,chemical and biological substances due to its advantages of small size,flexible structure,simple preparation,high sensitivity and label-free advantages.This thesis focuses on the sensing applications of MIM metamaterial absorbers for biological fields,and the main research is as follows:(1)The effects of different dielectric layer materials,metal materials and structural parameters on the absorption peak of MIM metamaterial absorber were investigated;single-band and dual-band MIM metamaterial absorber were designed,and the single-band metamaterial absorber achieved more than 82%absorption at the resonance wavenumber 1694 cm^-1,and the dual-band MIM metamaterial absorber achieved more than 88%absorption at the resonance wavenumber 1200 cm^-1 and 1952 cm^-1.The size dependence and polarization insensitivity of the MIM metamaterial absorber were analyzed,and its electric and magnetic fields and charge distributions were simulated;the equivalent Lorentzian model of tetrahedral deoxyribonucleic acid(TDN)probe and micro RNA(mi R-155)were constructed,the corresponding dielectric constants were extracted,and the biosensing detection capability of the MIM metamaterial absorber was theoretically analyzed.(2)According to the standard MEMS procedure,the single-band MIM metamaterial absorber chip was successfully developed,and the parametric characterization of device morphology and structure size was completed,the size of the chip reaches 5×5 cm²,and nearly 10000 sensing arrays can be obtained in a single flow,which shows that the device chip has significant advantages such as low cost and small size.The infrared absorption spectra of the processed chips were obtained based on the spectrometer analysis technique,and the experimental results matched with the simulation data,indicating the effectiveness of the processing process.(3)The detection performance of the MIM metamaterial absorber for nucleic acid molecule sensing was investigated,and the experimental results indicated that based on the surface-enhanced infrared absorption effect,the MIM metamaterial absorber can reach the detection limit of 500 p M for single-stranded deoxyribonucleic acid(DNA)and100 f M for short-stranded molecule mi R-155,with a sensitivity of 1.162%p M^-1.(4)The sensing detection method based on MIM metamaterial absorber and the traditional fluorescence detection technique were analyzed,and the results showed that the detection limit of the sensing detection method based on MIM metamaterial absorber(100 f M)is significantly lower than that of the fluorescence detection technique(10 p M),and the detection method has significant advantages such as small size,flexible structure,simple preparation,high sensitivity and label-free.