Research Of Nanophotonics Devices Based On Metallic Nanostructures

Based on the fantastic optical properties raised by the electromagneticenhancement of the metallic nanostructures in the optical waveband, thenanophotonics devices in applications are researched in this paper. The work isstarted by analyzing the properties of localized enhancement, sensitive to theenvironment refractive index, optical subwavelength modulation and opticalabsorption enhancement. By using the different properties of the one-dimensional,two-dimensional and three-dimensional metallic nanostructures, the devices ofsurface Plasmon resonance sensor, surface enhanced Raman scattering sensing chips,chip typed surface Plasmon spectrometer and wideband optical absorption chip areresearched, which are carried out with the theory designs, the devices fabricationsand function demonstrations by simulations or experiments. This work raises thenew ways to push the metallic nanooptics from physical property study to deviceapplication.The main contents and results of the paper are listed as bellow:(1) Based on the requirements of the sensitivity and stability in the surfacePlasmon resonance sensing, a sensor with one dimensional gold-silver bilayerednanofilm is proposed. The theory design method of the structure parameters and themechanism of the refractive index sensitivity enhancement are studied by analysisthe Fresnell’s law and Maxwell equations respectively. Based on the theory resultsthe sensing chip is fabricated and the system is set up. At last the chip is integratedin the surface Plasmon resonance imaging sensing instrument and a sensitivity of6.64×10-7RIU is achieved.(2) By utilizing the property of the surface interference in the subwavelengthmetallic slit-groove structure, a surface Plasmon thin film spectrometer, which canstick on the CCD optical detector array, is proposed. The spectrum recovery methodof this spectrometer is built by combining the surface Plasmon resonance theory andthe Fourier transform spectrum theory. By simulation, the function of thespectrometer is demonstrated and the results show that the frequencies of recoveredspectrum are correct and its shape is fit for the original spectrum.(3) In the surface enhanced Raman scattering sensing, the two-dimensionalmetallic nanoslit has the high sensitivity but suffers the hard fabrication of arrayed nanoslit structures. In this situation, two methods to fabricate arrayed metallicnanoslit convenient, fast and low cost are proposed in this work. One is based onprocess of etching the self-assembled polystyrene spheres to achieve the metallicnanoshell slit array. The fabrication result shows that the average width of thenanoslits is15nm. The other is based on the imprinting induced crack to achievenanoslit. The physical mechanism and parameter influence are analyzed by finiteelement simulation of the force in the structure, and the fabrication result shows thatthe width of the slit is30nm and the ratio of width to depth is larger than3:1.(4) Based on the theory model and simulation, the z direction couplingresonance mode of the three-dimensional nanostructure is studied. By analyzing theoptical field enhancement and absorption enhancement excited by this resonance,the sensing chip of the surface enhanced Raman scattering and the wideband, highefficiency absorption device is proposed. The experiment shows that theenhancement factor of the three-dimensional sensor is3.85times higher than thecontrol sample and the absorption device achieves the absorption ratio of93.9%atthe band of350nm-670nm.(5) The study of the three-dimensional composite metallic nanostructure iscarried out and the surface enhanced Raman scattering sensing device based on thesecondary localization enhancement of pyramid-particle composite structure isproposed. By analysis the theory of the primary localization and secondarylocalization, the parameters of the structure are optimized and the enhancementfactor of larger than109is obtained.