Research On Micro-nano Composite Structured Optical Surface Plasmonic Devices And Their Multi-characteristic Integration

Surface Plasmon Polaritions(SPPs)is a surface electromagnetic wave induced by the interaction between free electrons and photons on the metal-dielectric interface,it has some significant features such as breakthrough diffraction limit,subwavelength local and focusing,near field enhancement,super resolution imaging.These properties make surface plasmons with great application prospect'in the fields of subwavelength waveguide,high sensitivity optical sensing,high precision nano-lithography,high resolution microscope design and so on.Therefore,the recognition and exploration of surface plasmons excitation modes,transmission rules and regulation means will reveal its theoritical interaction mechanism between light and subwavelength micro-nano structure,also promote the exploration of surface plasmons based micro-nano optoelectronic devices,which improve the development for a new generation of tiny optoelectronic devices,and their integration.This thesis focuses on the designs and applications of micro-nano gratings,micro-nano array film structure and gold-coated nanodisk arrays.Based on the fundamental theory of surface plasmon.finite element method(FEM)and finite difference time domain(FDTD)method are used as the main numerical calculation tools in these work.From single and double metal grating structures to compound periodic double metal grating structure,we achieve a variety of spectral characteristics by debugging several typical structure parameters and obtain unconventional electromagnetic material properties.High absorption,extremely narrow band filtering,sensing and field intensity localization are highly integrated by using the composite structure of nanorod-film and nanordisk-film.Then,we conduct theoretical modeling,device fabrication and experimental research for Au-coated nanodisk arrays,and realize feature recognitions and detections of immunoglobulin and other biochemical molecules.This work can promote the research of nanoscale biochemical sensing technology in surface plasmon polaritons.Major research works are listed as follows:1.Based on the introduction of surface plasmon theory,typical numerical calculation methods and dispersion models of metal material,we first design a micro-nano grating with coated single-layer metal thin film and study its strange optical characteristics.Micro-nano grating can be used to realize bidirectional polarization filtering,optical signal modulation mechnism for photoelectric measurement and control applications.By calculating the reflection spectra of oblique incidence from the bottom and top of the designed structure,we find that the structure has the characteristic of bidirectional dual-channel narrowband polarization filtering and high broadband reflection characteristic of bidirectional no-polarization selectivity in near infrared range.It can be used to realize wavelength/intensity modulated sensing measurements,the filtering and sensing characteristics are compatible with angle based modulation.The SPP resonance and dipole resonance effect are main excitation mechanisms.The tunable filtering characteristic can be realized in visible and near infrared ranges by control structural period.This structure has certain guiding significance for developing micro-nano optoelectronic devices with the combination of bidirectional filtering,unpolarized high reflection in wide waveband,and high sensitivity sensing.2.We realize a multi-functional characteristic fusion under different period modulation by modeling and exploring of metal-dielectric-metal alternating film grating structure.Firstly,when the structural period is small as 200 nm,the abnormal optical transmission phenomenon is generated in ultraviolet-visible-near infrared regions,meanwhile,the structure presents a variety of unconventional electromagnetic material properties in near infrared area.Increasing the grating period to 400 nm.the structure shows tunable filter characteristics from purple light to red light in visible light band under different refractive index(RI)modulation.The generation of each filter wavelength is related to SPP and dipole resonance excitation at different positions.As the grating period increasing to 1000 nm,the narrow-band polarization filtering characteristic is obtained in specific infrared wavelength.When the period reaches 1550 nm,the grating demonstrates the characteristics of wavelength\intensity modulating sensing from RI insensitivity at P=1000 nm.The change of SPP resonance excitation position is a major inducing factor,and the RI sensitivity can reach 1556 nm/RIU.The design of this structure is valuable for making miniaturized,multifunctional and integrated micro-nano optical devices.3.Introducing a composite period in metal-dielectric-metal nanostructures,we investigate its spectral characteristics by parameters regulations.Through a series of researches on reflection,transmission and absorption spectra,we find that this structure can integrate characteristicses into one,which includes narrowband filtering and above 99%absorption for multi-channels.Furthermore,this nanostructure also realizes multi-channel sensing with wavelength/intensity interrogations,whose RI sensitivity is as high as 2080 nm/RIU.and the figure of merit can reach 92.1RIU-1.Comparing its characteristic spectra with single-period setting,the magnetic resonance,SPP resonance and F-P-like resonance play decisive roles for these properties.This structure can provide valuable approach for improving performance of surface plasmon resonance sensor and exploitation micro-nano optical devices with multi-channel integrating of narrowband filtering and perfect absorption.4.Using strong plasmon characteristics and low transmission loss characteristics of array-film combining structure,we design two types of array-film nano-structures,and realize their feature-rich regulations by coupling between plasma modes of nanoarrays and metal film.We design a nanostructure of film-coupled metallic nanorods with the elliptical hats.By analyzing and investigation dual-channel narrowband high absorption peaks,angular tolerance,RI sensing response characteristics and field enhancement effect,we find that the strong magnetic dipole interaction between nanorods and film can result in the largest local field enhancement up to 110 times,it is helpful to realize Raman spectroscopy detection of single molecule.Then,we design a polarization independent layered structure for hexagonal hybrid nanodisk arrays combined film,which has two narrowband peaks for high absorption,filtering and high sensitivity sensing in wide RI range.We compare its superiority with other plasmonic nanostructures by adjusting the arrangement of nanodisk arrays.These structures can accommodate future demands in designing multi-functional and highly integrated micro-nano optoelectronic devices.5.We develop a plasma sensor of Au-coated nanodisk arrays with breakthrough subwavelength scale,and realize biosensing detection of IgY and IgG.This Au-coated nanodisk structure is hexagonal and prepared by photolithography.By analyzing the transmission spectra at different incident angles and rotation angles,we reveal the physical mechanism of multiple plasmon resonant modes.We investigate its sensing performance of Au-coated nanodisk arrays based on optimal structural parameters for theoretical calculation and experimental measure-ment,and find that this structure generally has better sensing evaluation parameters including RI sensitivity,full width at half-maximum,figure of merit and RI resolution.Furthermore,when this sensor is applied to detection of IgY,its low detection limit is 5pg/mm2.In addition,we use this device for testing IgG in human urine,the result demonstrates that it has high sensitivity of biochemical detection in surface plasmon nanosensing technology.This detection of gold-coated nanodisk arrays is universal for other immunoglobulin molecules with further investigation.Based on the designs and explorations of micro-nano gratings,micro-nano array film structure and Au-coated nanodisk sensing element,we realize their feature-rich functions in filtering,high absorption,local field enhancement and protein biochemical detection.Combined with new nanomaterials and preparation technology,we will further research in the development of micro-nano optical devices for multi-functional integration.