The Research On The Coupling And Sensitivity Of Grating-like Nanoparticle Structures

It is possible to control and manipulate light by combinating of ultra-small size plasma nanostructures and metamaterials with extraordinary optical properties.Surface plasmon resonance sensors with local electric field enhancement characteristics have been widely used in biochemical detection.However,traditional nanostructures with plasma characteristics have unavoidable errors of high loss and strong dispersion,which will lead to a wider bandwidth in the spectrum and further weaken the performance of the sensor.Therefore,there are some big challenges,such as how to design the plasmon structure by optimizing the specific parameters to obtain low-loss that can control the resonance wavelength effectively,and how to design the plasmon structure with better local surface plasmon resonance and electromagnetic response phenomenon.In this paper,the resonance mechanism and sensing characteristics of the gratinglike nanoparticle structure composed of multiple gold square nanoparticles and gold nanorod are studied.Firstly,the local surface plasmon resonance effect of the gratinglike nanoparticle structure are studied with different sizes by using finite element methods.Compared with gold nanorod of the same length,this grating-like nanoparticle structure has smaller surface shape factor,a wider range of resonance wavelength,higher sensitivity and elevated quality factor.Secondly,we studied the local surface plasmon resonance effect when the gold square nanoparticles and the gold nanorod have a narrow gap.It is found that as the gap increases,the resonance wavelength has a blue-shift,and the resonance wavelength can be tuned.Finally,the coupling mechanism of the grating-like nanoparticle dimer structure are studied with different conditions,which can achieve higher sensitivity.The results showed that its sensing performance and filtering properties has many advantages and great prospect.