Research On Terahertz Tunable Electromagnetically Induced Transparency And Its Sensing Properties Based On Graphene Metamaterial

Due to its strong dispersion and slow light effect,electromagnetically induced transparency(EIT)effect has a wide application prospect in the field of micro and nano optics.In this paper,the tunable EIT effect and its sensing characteristics based on graphene metamaterials have been designed and studied in the terahertz band through the EIT mode coupling and the finite-difference time-domain method.The main contents are as follows:1.The EIT effect based on bright-dark mode coupling has been designed and researched.Through the graphene cutting line arrays,the actively tunable EIT effect can be achieved within the 0.2 to 1.2 terahertz band.By controlling the graphene’s Fermi level,the EIT window’s amplitude modulation can be realized,and the modulation depth can reach up to85.2%.In addition,the EIT window has the strong refractive index sensing performance with sensitivity up to 525.1 GHz/RIU.2.The EIT effect based on bright-bright mode coupling has been designed and researched.Through the asymmetric graphene loop arrays,the actively tunable EIT effect can be realized within the 4 to 8 terahertz band.The position and amplitude of EIT window can be modulated by adjusting the Fermi level,and the modulation depth can reach up to 80%.The sensing sensitivity of EIT transmission peak is 2.57 THz/RIU.3.The dual-window EIT effect based on bright-bright-bright mode coupling has been designed and researched.Through the graphene square loop-cutting line composite arrays,the actively tunable dual-window EIT effect can be realized within the 4 to 8 terahertz band.The overall amplitude modulation of dual EIT window can be achieved by adjusting the graphene’s carrier mobility.By adjusting the Fermi level independently,the single-side asynchronous amplitude modulation of dual EIT windows can be realized,and the modulation depth of dual EIT transmission peak can reach up to 58.3% and 73.5%,respectively.Moreover,the sensitivities of dual EIT transmission peaks are 2.45 THz/RIU and 2.64THz/RIU.4.The dual-window EIT effect with two parameters adjustable based on bright-bright-bright mode coupling has designed and researched.Through the graphene cutting line and split square loop composite arrays,the dual-window EIT effect with two parameters(the incident wave’s polarization angle and graphene’s Fermi level)adjustable can be realized within the 2 to 7 terahertz band.Meanwhile,the polarization angle can also switch the number of EIT window freely between 2 and 4.The sensing sensitivities of dual EIT transmission peaks can reach as high as 2.77 THz/RIU and 3.07 THz/RIU.