Design Of Subwavelength Hybrid Structure Micro/Nano Device Based On Surface Plasmon Effect

Surface plasmons(SPs)have two modes: surface plasmon polaritons(SPPs)mode propagating along the metal surface and localized surface plasmon(LSP)mode concentrating in the metal hole.Plasmonics,which is based on the enhance optical properties of SPs,has extensive applications in micro/nano photon devices such as photovoltaic cells and spectral imaging.In the past decade,the design of novel micro/nano devices based on surface plasmon effect has become an important research direction.In this work,the experimental process of interaction between light and periodic subwavelength hole arrays is simulated by finite-difference time-domain(FDTD)method.Herein,the enhanced light transmission characteristics of the periodic hybrid ring-slot structure hole arrays are investigated.A kind of micro/nano device based on the characteristics that whispering-gallery mode(WGM)can strengthen the local intensity of optical state in the structural environment is designed,which can be used in the field of sensor and optical switch.The main works are listed as follows:(1)Firstly,the basic principles of SPs are expounded.Moreover,overseas and domestic research status of WGM microcavity are reviewed.Lastly,the modeling and simulation process in FDTD method are introduced in detail.(2)The light transmission characteristics of different structures(ring,slot and hybrid ring-slot structures)hole arrays are simulated by FDTD method.It find that the ring structure,which can be regard as a WGM nanocavity,can greatly enhance the local intensity of optical state in the structural environment of the cavity,which almost doubles the transmission peak dominated by the slot mode.When the structural parameters of the slot of the hybrid ring-slot unit structure are changed,the interaction between the slot structure and the ring structure can be enhanced.Thus,the movement of the resonance peak becomes particularly sensitive.(3)A novel micro/nano device is designed and this design is verified by FDTD method.The micro/nano device has the advantages:WGM can enhance the local intensity of light field and LSP resonance has the sensitive response to the change of light field and unit structure parameters.We first designed a kind of plasmonic sensor having high sensitivity.Meanwhile,we design a novel plasmonic switch on the basis of sensing.The plasmonic switch having high switch ratio which can be up to 17.8 dB can be realized in two channels.The micro/nano device hasfollowing advantages: small mode volume,easy to integrate a quantum device,simple structure and easy to manufacture.