Research On Graphene-controlled Plasmonic Optical Tweezers And Nanoparticle Manipulation Technology

Surface plasmon is a special electromagnetic phenomenon that exists at the interface between metal and medium,where free electrons and photons interact.Surface plasmons can effectively break through the diffraction limit and achieve significant electric field enhancement in the near field region.Compared to traditional optical tweezers,optical tweezers based on plasmon resonance have many advantages such as strong optical force,wide capture range,and high accuracy.Graphene is a zero bandgap two-dimensional material with a hexagonal lattice arrangement of carbon atoms arranged in a single layer.Therefore,its electrical potential energy has dynamically tunable optical properties,which has important research significance in the field of plasmoic optical tweezers.This article conducts multiple studies on graphene modulated plasma optical tweezers systems,which can be applied in fields such as biomedicine,nanoassembly,and enhanced Raman sensing.In this paper,we mainly studied the technology of plasmoic optical tweezers and nanoparticles manipulation based on graphene regulation.Firstly,it introduces the research background of optical tweezers,analyzes the basic principle of optical tweezers,explores the classification and application of optical tweezers,and combs the research progress and representative achievements at home and abroad;Then,the principle of plasmon and the numerical calculation model of optical force are studied;Two numerical research methods,finite element method(FEM)and finite difference method(FDTD),are discussed.Finally,three kinds of plasmoic optical tweezers are designed based on graphene material,which can realize the dynamic transport of nanoparticles in a plane,the separation of nano chiral particles,and the reflective focusing lens optical tweezers.The specific research contents are as follows:1: An integrated multifunctional graphene disk 2D plasmonic optical tweezers technology is posed,which consists of a graphene disk array and a substrate circuit.A bias voltage can be applied through a substrate circuit to independently configure the Fermi level of the graphene disk,thereby controlling the position of plasmon resonance excitation,and dynamically transporting nanoparticles to any position in the 2D plane.The device has the characteristics of integration and multi-function,and can be independently applied to capture,transport,classify,and fuse nanoparticles.2: A chiral particle separation microfluidic cavity based on graphene strip is posed.Plasmon resonance excited by chiral circularly polarized light also has chiral characteristics.Under the excitation of incident light,the plasmon resonance generated by graphene can amplify the intensity of the chiral field,and form a very strong electric field resonance enhancement on the surface of the graphene band.The results show that the enantiomeric nanoparticles can be effectively separated.3: A reflective metasurface lens optical tweezers system is posed.By controlling the Fermi energy level of graphene,different phase delays can be caused to the reflected electromagnetic wave.By controlling the Fermi level of graphene separately,we can control the position of the focus in the plane.The numerical study shows that the control of the medium particles can be realized by controlling the position of the focus.