| Hyperbolic metamaterial is an electromagnetic medium with anisotropic dielectric constant tensor or permeability tensor,and is a uniaxial structure material with hyperbolic scattering.The internal plasmon of the hyperbolic metamaterial can make the light of high-k wave vector have strong transmission ability,so the resonance of the bulk plasma of the hyperbolic metamaterial can be realized by wave vector matching to achieve high sensitivity biosensing.The rod-shaped three-dimensional porous hyperbolic metamaterial in this paper has the advantages of larger specific surface area,pore structure to adsorb more biomolecules and the realization of self-wave vector matching to excite the plasmon of the hyperbolic metamaterial body.Materials are used in biosensors.(1)Through the FDTD simulation,the optical sensitivity mechanism of the layered and rod-shaped hyperbolic metamaterials was studied.In the high reflectance region of the reflection spectrum,some valleys exhibited by bulk plasma primitives will appear.When the dielectric constant of the layered hyperbolic metamaterial of gold and aluminum oxide is greater than 585 nm,a non-positive definite interval appears.In the non-positive definite area,a reflection valley appears in the high-reflection region after 550 nm.The wavelength of the reflection valley is 674 nm.At 748 nm and 1103 nm,the dispersion energy state mode diagrams appear to match ?2.7 × 1014 Hz,?4.0 × 1014 Hz,and ?4.5 × 1014 Hz.The non-positive definite interval of the hyperbolic metamaterial of platinum oxide-coated silicon oxide rod is in the range of 600 nm to 1600 nm.The wavelength of the concave valley of reflection in the non-positive definite interval is 680 nm,and the dispersion band mode corresponding to the concave valley is ? 0.26 × 10 ^ 15 Hz.The metal oxide-coated silicon oxide rod reflects the concave valley at a wavelength of 1300 nm,and the corresponding dispersion mode of the concave valley is ? 0.135 × 10 ^ 15 Hz.In the non-positive definite interval of the hyperbolic metamaterial,the light-wavevector matching can excite the volume plasmon energy state mode of the hyperbolic metamaterial in the reflection spectrum as a reflection-shaped concave valley.(2)Research on the construction and performance of three-dimensional porous metamaterials.First,titanium oxide inverse opal was used to deposit gold nanoparticles and the performance of the structure was studied: the structure of the opal was constructed by self-assembly deposition of polystyrene microspheres,and the thickness of the surface of the polystyrene microsphere opal spheres was controlled to be oxidized by atomic layerdeposition Titanium thin layer,calcined at 400 ? for 1 hour to remove polystyrene microspheres to obtain porous titanium oxide inverse opal structure;polyvinylpyrrolidone as a stabilizer,sodium borohydride and sodium citrate as reducing agents,chloroauric acid as a gold source,through The immersion method grew the gold nanoparticles into the pore structure of titanium oxide inverse opal.After characterization,it was found that the monodisperse gold nanoparticles were spherical or ellipsoidal,with a size of 13nm-45 nm.The reflection spectra of the inverse opal structure before and after loading gold nanoparticles were studied by FDTD simulation and experimental spectral testing.The localized plasmon peaks of the reflection spectrum were all around 520 nm,and the photon band gap peaks were all around 650 nm.After completing the loading of the porous colloidal structure with gold nanoparticles,the construction and performance of the hyperbolic metamaterials of precious metal-coated silica nanorods were carried out: an emulsion of silicon oxide nanorods synthesized by hydrolysis of tetraethylorthosilicate,centrifugal washing and purification of the same size Silicon oxide nanorods,changing the amount of ethyl orthosilicate to obtain 1.7?m and 3.2?m silicon oxide rods;vertical template and horizontal template of silicon oxide nanorods were synthesized by selfassembly method of applied electric field;by atomic layer deposition method The surface of the silicon oxide rod of the vertical template is coated with metallic platinum and metallic copper,and silver nitrate is reduced by glucose to electrolessly plate silver on the surface of the horizontal template to construct a hyperbolic metamaterial of the precious metal-coated silicon oxide nanorod.SEM characterization sees the three-dimensional period of hyperbolic metamaterials Porous rod-shaped structure,EDS and XPS determined that the content of metal platinum is 27.89% and the content of metal copper is 0.52%.The spectrum study found that: for the hyperbolic metamaterial of metal platinum-coated silicon oxide rod,the reflection spectrum body obtained by experiment and simulation The plasmon valleys basically agree,and the wavelengths are all around 660 nm.The reflection spectrum of the copper-coated silicon oxide rod experimental test is between 600nm-800 nm,but the simulated spectrum is slightly different due to interference.But their reflectivity and transmittance both decrease with increasing thickness.In this way,we successfully constructed a porous metamaterial structure experimentally and the structure possessed the concave valley of the characteristic of plasmon reflection.(3)Three-dimensional porous rod-shaped metamaterial biomolecule loading and biosensing research.First,the titanium oxide inverse opal loaded with gold particles was used for biomolecule loading and biosensing research: after adjusting thep H with phosphate buffer,different concentrations of cysteine biomolecules selfassembled to gold nanoparticles through gold-sulfur coordination bonds After adjusting the p H,the blood glucose proteins of different concentrations are linked to the cysteine biomolecules through the condensation reaction.SEM characterization observed that the biomolecules covered the gold particles;EDS characterization observed that the S element content was 0.43%,which confirmed that the biomolecules were loaded on the gold particles.For different concentrations of glucose protein molecules,the wavelength shift was approximately linear.More importantly,biomolecular loading and biosensing studies were carried out on the constructed precious metal-coated hyperbolic metamaterials: the metal platinum-coated hyperbolic metamaterials were sequentially prepared with 10 m M cysteine and different concentrations of glycemic proteins.Biomolecular loading was carried out;SEM characterization observed that biomolecules covered the surface of the rod,and EDS characterization observed that the S element content was 0.55%.The detection sensitivity of the platinum hyperbolic metamaterial is 8nm / m M,which is higher than the detection sensitivity of the porous structure loaded with gold particles of 5nm / m M,and it has more advantages in sensing.For the goldcoated horizontal rod-shaped hyperbolic metamaterial biomolecule loading and biosensing research: the three media of air,water and ethanol were coated with 10 nm,and the plasmon valley at a wavelength of 1300 nm in the reflection spectrum The maximum sensitivity of the sensor can reach 33.89 nm / RIU;when the ethanol molecules of different thickness are loaded on the gold hyperbolic metamaterial,the characteristic peak(valley)wavelength of the reflection spectrum of different mechanisms changes linearly with the thickness,and the different reflection characteristic peaks(Valley)The detection sensitivity is 18.19 nm / RIU(LSPR ?520nm),79.31 nm / RIU(SPP ?600nm),124.79 nm / RIU(SPP ?650nm),33.28 nm / RIU(VPP?1300nm)),and the surface plasmon at a wavelength of 650 nm The highest detection sensitivity of excitons is124.79 nm / RIU.Through sensitivity analysis,it is fully shown that the application of precious metal-coated hyperbolic metamaterials in high-sensitivity biosensing has broad prospects. |
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