Tunable multi-frequency ultrasensitive terahertz sensor based on a graphene metamaterial absorber
In order to achieve highly sensitive and label-free rapid detection of biologicals,a multi-band tunable absorber with a graphene-dielectric-gold structure that can be used as a terahertz(THz)sensor is proposed using the finite element method(FEM)in COMSOL Multiphysics software for modeling and numerical analysis.The strong interaction between the graphene surface plasmon resonance(SPR)and the absorber produces four ultra-narrow perfect absorption peaks,and the frequency of the resonance can be adjusted by tuning the chemical po-tential of graphene over a wide range.In addition,in both transverse electric(TE)and transverse magnetic(TM)modes,the absorber can also excite strong surface plasmons when the oblique incidence angle is close to 80°.The simulation results show that,as a refractive index sensor the proposed structure can achieve maximum sensitivity of 2.458 THz/RIU,Q factor of 230.258,and figure of merit(FOM)of 73.323 RIU-1.Therefore,compared with the traditional refractive index sensors,the designed high-performance sensors have higher sensi-tivity and better sensing performance,which has a wider application prospect in biomedical diagnosis and envi-ronmental monitoring.
graphenesurface plasmon resonancemulti-band absorberrefractive index sensor
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