Research On High Q Resonance And Electromagnetically Induced Transparency In All-dielectric Metamaterial

Metamaterial?MM?is a kind of artificial electromagnetic composite material which has subwavelength periodic structures.Resonance is the fundamental characteristic of metamaterial and high quality factor?Q?resonance can be achieved by high Q electromagnetic resonance or electromagnetically induced transparency?EIT?.High Q metamaterial resonators have received much attention due to their important applications in high-sensitivity sensing,narrow-band filtering,electromagnetic wave modulation,optical storage,and slow-wave devices.MM include metal metamaterial and dielectric metamaterial.Due to the ohmic loss of the metal metamaterial,this mainly limits the implementation of high Q,and especially in the optical band,the metal loss is larger.All-dielectric metamaterial avoid the generation of ohmic losses,which provide another way to achieve high Q resonance.However,there are still few reports in this area.The main research work includes:?1?High Q-factor electric and magnetic resonator in symmetric all-dielectric metamaterial is designed.The resonator consists of quartz substrate and an array of rectangular silicon bars on the substrate.When the incident electric field is perpendicular to the silicon bars,the Mie electric resonance(dielectric resonator TE_12?mode)of the silicon bars can be excited.By adjusting the distance between bars and bars,a strong near field coupling can be achieved,thereby the Q-factor of resonant increasing and the Q-factor can up to 10⁴.In addition,when the incident electric field is parallel to the silicon bas,high Q Mie magnetic resonance(dielectric resonator TM_12?mode)can also be achieved.?2?When a slab waveguide combined with metamaterial which is regarded as a grating,an all-dielectric electromagnetically induced transparent metamaterial resonator based on guided mode resonance is designed.The resonator structure consists of quartz waveguide layer and two-dimensional periodic dielectric silicon bars on the waveguide layer.Through the diffracting effect of the two-dimensional dielectric bars,the incident electromagnetic wave can couple into the waveguide layer,and EIT-like effect can be achieved by destructive interference between the low Q Mie resonance and high Q guided mode resonance.By adjusting the geometric parameters of the silicon bars,the depth of the grating modulation can be changed to achieve a high Q resonance.The Q-factor of the simulation calculation can reach 27000 and the group refractive index is 5000.?3?An electromagnetically-induced transparent all-dielectric metamaterial resonator of S-shaped is proposed.The resonator consists of"S"type silicon strip and quartz substrate.By destroying the symmetry of the"S"type structure,EIT-like effect can be achieved by destructive interference between the low Q toroidal dipole resonance and the high Q magnetic dipole resonance.The Q-factor of EIT-like resonant is as high as 10⁴ and the amplitude is maintained above 0.85.The sensitivity for refractive index sensing is 335 nm/RIU.?4?As a comparison with all-dielectric metamaterial resonator,we design and fabricate S-shaped electromagnetically induced transparent metal metamaterial resonator.This structure also by destroying the symmetry of the S-shaped structure to achieve the regulation of the EIT resonance,and the calculated Q-factor is up to 54without considering the loss of the substrate material.Due to the actual material loss and the limitation of the experimental error,the Q-factor obtained in the experiment is 14 and consists with the numerical calculation.