Design Of Superstructured Surfaces For Nanofocusing Hotspot Arrays

Metallic nanoscale metamaterials,such as nanoplasmonic and nanophotonic surfaces and structures,have attracted extensive attention due to their unique physical properties and promising applications in various fields,such as biosensing,illumination,and imaging.When interacting with light,these structures generate plasmonic resonances,resulting in the coupling of localized surface plasmon resonances(LSPR)and the formation of bright spots called "hot spots" on the structure surface.Hot spots can confine light in subwavelength regions,breaking the diffraction limit.The design and fabrication of metallic nanoscale metamaterials require precise control over the size,morphology,and arrangement of metal nanostructures to achieve desired optical responses,enabling a range of applications including biosensing,surface-enhanced Raman scattering,and enhanced sensing.The main research work of this paper is as follows:1.The characteristics of metal nano-super surface structures were theoretically studied,and a simulation model of the gold cone array super surface structure with a metal-dielectric-metal(MIM)sandwich structure was established.The influence factors of tip focusing and electric field enhancement effects were analyzed.Through changing the optical parameters of the incident light source and the geometric parameters of the structure,the tip focusing and electric field enhancement effects were controlled to achieve the optimal performance of the structure.2.MIM-type gold cone array super surface structure samples were prepared by heavy ion track membrane method,and the optical properties of the samples were tested experimentally.Firstly,the electromagnetic "hot spots" excited on the sample surface were characterized by near-field optical scanning experiments,and their optical characteristics and light intensity distribution were studied.Secondly,the absorption spectra of the sample in air and different concentration solutions were measured by a spectrophotometer,and the LSPR characteristics presented in different concentration solutions were studied.Research results indicate that the tip of MIM-type metal cone array superstructures can realize nanofocusing and local field enhancement effects.By adjusting the incident light source and structure parameters,the tip nanofocusing and field enhancement effects can be effectively controlled.Near-field optical scanning experiments verify the sample’s high-precision nanofocusing ability,and absorption spectroscopy experiments confirm the sample’s high sensitivity.Utilizing the optical characteristics of the structure,it can have important applications in biosensing,surface-enhanced Raman scattering,and enhanced sensing.