基于相变材料的慢光和吸收可切换多功能太赫兹超材料  

Switchable multifunctional terahertz metamaterial with slow-light and absorption functions based on phase change materials

作　　者：金嘉升 马成举[1] 张垚 张跃斌 鲍士仟 李咪 李东明[1] 刘洺 刘芊震 张贻歆 Jin Jia-Sheng;Ma Cheng-Ju;Zhang Yao;Zhang Yue-Bin;Bao Shi-Qian;Li Mi;Li Dong-Ming;Liu Ming;Liu Qian-Zhen;Zhang Yi-Xin(School of Science,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]西安石油大学理学院,西安710065

出　　处：《物理学报》2023年第8期141-148,共8页Acta Physica Sinica

基　　金：西安石油大学创新与实践能力培养项目(批准号:YCS20213210)资助的课题.

摘　　要：基于相变材料Ge_(2)Sb_(2)Te_(5)(GST)设计了一种太赫兹超材料,在太赫兹波段实现了慢光和吸收功能的切换.该超材料由三部分构成,分别是金环构成的微结构层、SiO_(2)介质层和GST薄膜.研究结果表明:当GST薄膜处于绝缘态时,由于两个谐振环的电磁诱导透明效应,入射THz光脉冲通过该THz超材料时群速度会减慢,最大群延迟可以达到3.6 ps;当GST薄膜转变为金属态时,THz超材料可实现双波段吸收,在0.365 THz处吸收率可以达到97%,在0.609 THz处吸收率可以实现完美吸收(吸收率100%).另外还研究了该THz超材料的入射光偏振不敏感特性,发现当入射光脉冲的偏振角从0°变化到90°时,THz超材料的慢光和吸收特性不受影响.所设计的THz超材料在光缓存器、光传感器、光开关等领域具有潜在的应用价值.Terahertz(THz)wave usually refers to the electromagnetic wave with a frequency between 0.1—10.0 THz.It has potential applications in wireless communication,biomedical image processing,nondestructive testing,military radar,and other fields.However,owing to function limitation of the natural material,multifunctional terahertz devices are difficult to design and fabricate,which becomes a bottleneck for THz technology.The emergence of metamaterials fills the gap in the electromagnetic materials in the THz frequency band,and now they are widely used in THz functional devices,such as THz modulators,THz absorbers,THz filters,THz sensors,and THz slow-light devices.However,the above-mentioned THz devices all have a single function.For practical application,multifunction integrated THz devices have broader application prospects.As is well known,the Ge_(2)Sb_(2)Te_(5)(GST)is a typical phase transition material.Under excitation of light or electronic field,GST can realize a reversible phase transition between insulating state and metallic state.In order to achieve a switchable multifunctional THz device,in this work we design a THz metamaterial based on the phase transition material GST and realize a switchable function with slow-light and absorption functions.The THz metamaterial consists of a microstructure layer,which is composed of gold rings arranged periodically,and a GST thin film spaced by an SiO_(2) dielectric layer.When GST is in an insulating state,the two gold rings are coupled to each other under the excitation of the THz pulse.Then,we can observe the EIT-like effect.The THz pulses propagating in the metamaterial we proposed can be slowed down,and a maximum group delay of the THz pulse can reach 3.6 ps.However,when GST is in a metallic state,we can observe two absorption peaks in the spectrum of the proposed THz metamaterial,and the absorption rate is 97%at a frequency of 0.365 THz and 100%at a frequency of 0.609 THz.Furthermore,we also investigate the polarization properties of the proposed THz metamaterial,a

关 键 词：超材料 太赫兹 慢光 吸收器 相变材料 

分 类 号：TB34[一般工业技术—材料科学与工程]