Research Of Terahertz Metamaterial Biosensing Chips

Based on low photon energy and without ionizing damage on biological materials of terahertz(THz)wave and the characteristics of surrounding dielectric environment sensitivity of resonance frequency of metamaterials composed of metal micro-nano structures,THz metamaterial biosensing chips have been exploratively studied in this paper.Through the analysis of current practical problems of THz biosensing chips used in the detection of biological macromolecules,subwavelength metallic arrays structure,polarization-insensitive four split ring resonator arrays structure and multiple split ring resonator arrays structure are proposed,studies of theory analysis and designs,devices fabrications and sensing experimental verifications of three biosensing chips are carried out.This work lays the foundation for building a general and high sensitive THz detection means of biological materials.The main contents of the paper are listed as fellows:(1)A THz sensing chip composed of subwavelength metallic arrays is firstly proposed.Combined with the equivalent medium theory and FP resonance theory,the relationship between the offset amount of chip's resonance frequency and the dielectric constant of analyte,structural parameters is analyzed and the sensing theory model of the chip is established.The structure is fabricated by the orthogonal lithography process.The sensing experimental result indicates that the resonance frequency shifted 53 GHz for 0.025 mol/L water solutions of D(+)-glucose.(2)In view of the strong linear polarization of common used THz time domain wide spectrum system in biological detection,the resonance frequency of sensing chip changes significantly with the difference between its placed direction and the polarization direction of system.In order to solve this problem,a sensing chip composed of four split ring resonator arrays is proposed.Combined with the finite element method,the structural parameters of the sensing chip are optimized and then the sensing chip is fabricated.The sensing experimental result indicates that the uncertainty of the sensing chip is 1.68 GHz,275 GHz shifted frequency is obtained for 3.0 mmol/L Albumin from bovine serum(BSA)water solutions,the sensitivity is 95 GHz/(mmol/L)and the minimal resolution of BSA solutions with the sensing chip is 17.7 ?mol/L.(3)To provide rich biological information,a THz sensing chip composed of multiple split ring resonator arrays is constructed.By theoretical simulation,the optimization of its structural parameters is completed.The corresponding sensing chip is prepared by the means of photon lithography process.Finally,the application in DNA,protein and bacteria shows the sensor has two characteristic peaks.According to different offset of two characteristic peaks,the distinguish of different types of bacteria,different chain length of DNA and different concentrations of protein is achieved.The result provide good evidence for the versatility and flexibility of proposed THz metamaterial sensing chips.