基于石墨烯超材料吸收体的可调谐多频超灵敏太赫兹传感器

Tunable multi-frequency ultrasensitive terahertz sensorbased on a graphene metamaterial absorber

为了实现对生物高灵敏、无标记的快速检测,采用COMSOL Multiphysics软件中的有限元法(FEM)进行建模和数值分析,提出了一种具有石墨烯-电介质-金结构的多频带可调谐吸收体,该吸收体可用作太赫兹(THz)传感器.石墨烯表面等离子激元共振(SPR)和吸收体之间的强相互作用产生四个超窄的完美吸收峰,并且可以通过在较宽范围内调谐石墨烯的化学势来调整共振频率的位置.此外,在横电(TE)和横磁(TM)模式下,当斜入射角接近80°时吸收体均也可以激发强的表面等离激元.模拟结果表明,所提出的结构作为折射率传感器可实现最大灵敏度、Q因子和品质因数(FOM)分别为2.458 THz/RIU、230.258和73.323 RIU^(-1).因此,相对传统的折射率传感器,所设计的高性能传感器拥有更高的灵敏度和更好的传感性能,在生物医学诊断和环境监测方面具有更广的应用前景.

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 potential 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 sensitivity and better sensing performance,which has a wider application prospect in biomedical diagnosis and environmental monitoring.