| Terahertz to far infrared waveband has a broad application prospect,but its development is limited due to the lack of devices operating in this waveband.Graphene supports surface plasmonic resonance(SPR)in terahertz to far infrared waveband,and graphene can be utilized to realize several optical applications such as polarizing,absorbing and splitting.At the same time,since the conductivity of graphene can be tuned with the changing of applied voltage,the SPR frequency possesses the electrically tunable feature which can be used to realize electrically tunable applications in terahertz to far infrared waveband.This article focused on the research of SPR effect of nano-structured graphene,and designed a transmission-type electrically tunable polarizer in terahertz waveband and an electrically tunable polarization splitter in far infrared waveband by using the SPR effect of graphene.The main contents are listed as follows:1.The dispersion mode of graphene was analyzed and the biased voltage needed for electrical doping of graphene was estimated.2.The dispersion characteristics of plasmonic resonance mode supported by graphene ribbons were analyzed by using FP model.3.A transmission-type polarizer at terahertz waveband was proposed and designed.The numerical simulations results show the polarizer obtains about 20 dB’s polarization ratio at terahertz waveband.And the operating wavelength of the polarizer can be tuned by controlling the applied voltage.The proposed structure is very suitable for integration since the period of the structure is 1 μm,which is far less than the operating wavelength of 50 μm.4.A polarization splitter at far infrared waveband was proposed and designed.The numerical simulations results show that the designed splitter obtains the transmitting splitting ratio of 20 dB and the reflecting splitting ratio of 28 dB.And the operating wavelength can be also tuned through changing the applied voltage. |
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