Realization Of Plasmon Induced Transparency With Metamaterials And Its Electromagnetic Properties

Metamaterial is a new type of artificial material.Through the design of periodic unit structure,it can obtain the extraordinary physical properties that are not possessed by the conventional materials in nature.And the size of metamaterials is usually at micrometer or nanometer scale,so it is easy to make integrated devices.Therefore,metamaterials has a wide range of application in fields such as electromagnetics,thermals,materials science and energy.When electromagnetic waves are incident on the metal surface,its free electrons are coupled with the incident electromagnetic waves to generate periodic collective oscillations,forming surface plasmons.Combining metamaterials with plasmons to achieve a phenomenon similar to electromagnetically induced transparency,namely plasmon induced transparency.It greatly reduces the experiment conditions,and can flexibly manipulate the EIT effect,making plasmon induced transparency a research hotspot in recent years.In this dissertation,two different metamaterial structures are designed and their optical properties are studied theoretically based on COMSOL Multiphysics calculation methods.Two structures are metallic metamaterial transmitters in visible-waveband and graphene based metamaterial transmitters in terahertz-band.And some numerical results are listed as following:1.We proposed a three-dimensional metamaterial based on three identical metal rings to achieve tunable plasmon-induced transparency phenomenon.By rotating or moving the middle ring,it is found that an on-to-off amplitude modulation of the PIT transparency window can be achieved and the two kinds of regulation produces different spectral effects.When moving the intermediate ring,two dips move in both directions of the high and low frequencies respectively,that is,the width of the transmission peak become larger,when the intermediate ring is rotated,the position and width of the transmission peak both remain fixed and only the intensity of the transmission peak increases.The destructive interference between the electric dipole and the quadrupole modes can reveal the cause of the PIT effect.Moreover,the coupling mechanism of PIT effect is theoretically explained based on the classical two-oscillator models.The maximum refractive index of the designed structure can reach 352 in the visible frequency range with a significant slow light effect.The position of the transmission peak can be adjusted by changing the main and outer radius of the ring.2.We presented a two-dimensional planar metamaterial based on graphene self-symmetrical H-shaped resonators,and the tunable plasmon induced transparency effect is realized through controlling the polarization direction of the incident field.Without changing any structural parameters,the transition from transmission(PIT mode)to non-transmission(even sub-mode)can be achieved simply by changing the polarization angle.The origin of PIT mode is revealed by magnetic dipole induced coupling and phase coupling.By further changing the Fermi energy of graphene,the resonance frequency and amplitude of the transmission peak can be effectively adjusted,and the maximum modulation depth can reach up to 60.7%.To investigate its applications in the sensor device,its sensitivity to the refractive index of the substrate can reach 5619.56 nm/RIU.