提出基于棱镜-空气-石墨烯-石英-硅结构, 通过外加电场改变石墨烯的介电常数, 引起太赫兹波反射率的变化, 并利用等离子体共振机理对反射太赫兹波强度控制以实现太赫兹波开关功能.研究了空气隙对太赫兹波反射率的影响,结果表明: 当空气隙为20 μm时, 太赫兹波反射率最小值为68.79%, 当空气隙为56 μm时, 太赫兹波反射率最小值降至0.04%, 此时的空气隙达到最佳值.分析确定了石墨烯化学势对太赫兹波反射率的影响, 结果表明: 当石墨烯化学势从0 eV增加到0.2 eV, 太赫兹波的反射率从零增加到95.89%, 从零反射变成全反射, 表明该结构具有优异的反射太赫兹波强度控制性能, 开关的消光比达到33 dB.

A terahertz wave switch based on prism-air-graphene-quartz-Si structure was proposed. The dielectric constant of grapheme was changed by the applied external voltage , which make the terahertz wave reflectivity dramatically was changed. The plasma resonance mechanism was used to control of reflected terahertz wave intensity and realize the function of terahertz wave switch. Firstly, the influence of air gap distance on terahertz wave reflectivity is studied. The results show that when air gap is 20 μm, the minimum value of terahertz wave reflectance is 68.79%, When air gap is 56 μm, the minimum value of terahertz wave reflectance is reduced to 0.04% and the air gap distance reaches the optimum value. Secondly, the influence of graphene chemical potential on terahertz wave reflectivity was determined. The results show that when the chemical potential of graphene increases from 0 eV to 0.2 eV, the reflectivity of terahertz wave increases from zero to 95.89% and changes from zero to total reflection. The numerical results also further show that the proposed structure has enormous potential for terahertz wave switch with the extinction ratio of 33 dB.