| Unlike traditional antennas,nano-antennas can effectively convert the energy of the propagation field and the local field in the optical band,which has become a research hotspot in the field of nanophotonics.Changing the size of the nano-antenna can adjust its operating frequency to a certain extent.By adjusting its construction parameters,the nano-antenna can be operated in the visible and near-infrared bands commonly used in quantum communication.Subwavelength nano-antennas interact with incident light at light-wave frequencies to exhibit physical properties such as isosurface excitons.Surface plasmons are often used to solve the problem of difficult miniaturization and integration of optical devices due to their ability to break through diffraction limits and enhance local field enhancement.Therefore,the surface plasmon characteristics in the antenna can be utilized to enhance communication properties such as directivity and radiation intensity in its operating frequency band.In this paper,the theory of surface plasmons and nano-antennas is firstly described.Then the radiance attenuation rate and quantum efficiency of several different structures of nano-antennas are simulated by using the finite difference time domain method.The best bow tie shape is selected.As the basic antenna model in the next work,the antenna is coupled with the lens-shaped nano-antenna and the graphene and micro-cavity structures respectively to calculate the scattering cross-section,absorption cross-section and directionality,and compare the two materials made of gold and silver.The simulation of the antenna finally resulted in the coupling between the nano-antenna and the optics of different structures and materials.The theory and simulation of this paper are of great significance for the study of nano-optical antennas. |
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