基于石墨烯-二氧化钒的太赫兹双控可调宽带吸收器  

Dual-Control and Tunable Broadband Terahertz Absorber Based on Graphene-Vanadium Dioxide

作　　者：朱华利 张勇[1] 叶龙芳 党章[1] 徐锐敏[1] 延波[1] Zhu Huali;Zhang Yong;Ye Longfang;Dang Zhang;Xu Ruimin;Yan Bo(Fundamental Science on EHF Laboratory,University of Electronic Science and Technology of China,Chengdu 611731,Sichuan,China;Institute of Electromagnetics and Acoustics,Department of Electronic Science,Xiamen University,Xiamen 361005,Fujian,China;Shenzhen Research Institute of Xiamen University,Shenzhen 518057,Guangdong,China)

机构地区：[1]电子科技大学极高频复杂系统国防重点学科实验室,四川成都611731 [2]厦门大学电子科学与技术学院电磁声学研究院,福建厦门361005 [3]厦门大学深圳研究院,广东深圳518057

出　　处：《光学学报》2022年第14期194-200,共7页Acta Optica Sinica

基　　金：国家自然科学基金(61871072)。

摘　　要：提出了一种基于石墨烯和二氧化钒(VO_(2))混合材料的双控太赫兹超材料宽带吸收器,该吸收器具有结构简单、吸收/透射/反射状态可切换、调谐深度大等优点。吸收器的吸收率的调控可以通过改变VO_(2)的相变特性及石墨烯的费米能级来实现。当VO_(2)处于金属态时,该吸收器在1.07~2.59 THz频率范围内可实现吸收率大于90%的宽带吸收,且具有偏置无关和宽入射角不敏感特性,通过改变石墨烯的费米能级,可对带内吸收率进行动态调控,可调范围大于67.2%。当VO_(2)处于绝缘状态,该器件表现为由石墨烯费米能级调控的可调透射器,透射率可调范围大于40%。进一步地,同时控制VO_(2)相变特性和石墨烯费米能级,可将吸收器的带内吸收率的可调范围提升至90%以上,最大可调范围为99.7%@2.3 THz,实现了吸收率的完美开关特性。该吸收器通过两个独立可控的超材料实现了具有高调谐特性的太赫兹双控吸收器,在太赫兹智能器件(如衰减器、反射器和空间调制器等)领域具有潜在的应用价值。This paper proposes a dual-control adjustable terahertz metamaterial broadband absorber based on a mixed material of graphene and vanadium dioxide(VO_(2)).The absorber has the advantages of simple structure,switchable absorption/transmission/reflection,and large modulation depth.The absorptivity control of the absorber can be achieved by changing the phase transition characteristics of VO_(2)and the Fermi energy level of graphene.When VO_(2)is in a metallic state,the absorber can achieve broadband absorption with an absorptivity greater than 90%in the frequency range of1.07-2.59 THz,and exhibits excellent absorption performance under a wide range of incident and polarization angles for TE and TM polarizations.By changing the Fermi energy of the graphene,the in-band absorptivity can be dynamically adjusted,and the modulation depth is greater than 67.2%.When VO_(2)is in an insulating state,the device behaves as an adjustable transmission mode regulated by the graphene Fermi energy level,with a transmittance modulation depth greater than 40%.Furthermore,by controlling both the VO_(2)phase transition characteristics and the graphene Fermi energy level,the in-band absorptivity modulation depth of the absorber can be increased to more than 90%,and the maximum modulation depth is 99.7%.The absorber realizes a terahertz dual-control absorber with good tuning characteristics through two independently controllable materials,and has potential applications in the field of terahertz smart devices(such as attenuators,reflectors,and spatial modulators).

关 键 词：光学器件 超材料吸收器 太赫兹 可调节 宽带 

分 类 号：TB34[一般工业技术—材料科学与工程]