College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), Tianjin, 300072, China.
School of Electrical and Computer Engineering Oklahoma State University, Stillwater, OK, 74078, USA.
Small. 2016 May;12(19):2610-5. doi: 10.1002/smll.201600276. Epub 2016 Mar 23.
Metamaterials, offering unprecedented functionalities to manipulate electromagnetic waves, have become a research hotspot in recent years. Through the incorporation of active media, the exotic electromagnetic behavior of metamaterials can be dramatically empowered by dynamic control. Many ferroelectric materials such as BaSrTiO3 (abbreviated as BST), exhibiting strong response to external electric field, hold great promise in both microwave and terahertz tunable devices. A new active Ba0.6 Sr0.4 TiO3 -silicon hybrid metamaterial device, namely, a SRR (square split-ring resonator)-BaSrTiO3 thin film-silicon three-layer structure is fabricated and intensively studied. The active Ba0.6 Sr0.4 TiO3 thin film hybrid metamaterial, with nanoscale thickness, delivers a transmission contrast up to ≈79% due to electrically enabled carrier transport between the ferroelectric thin film and silicon substrate. This work has significantly increased the low modulation rate of ferroelectric based devices in terahertz range, a major problem in this field remaining unresolved for many years. The proposed BST metamaterial is promising in developing high-performance real world photonic devices for terahertz technology.
超材料为操控电磁波提供了前所未有的功能，近年来成为研究热点。通过引入有源媒质，超材料的奇异电磁行为可以通过动态控制得到显著增强。许多铁电材料，如 BaSrTiO3（简称 BST），对外电场具有很强的响应，在微波和太赫兹可调谐器件方面具有很大的应用前景。一种新的有源 Ba0.6 Sr0.4 TiO3-硅混合超材料器件，即 SRR（方形分裂环谐振器）-BaSrTiO3 薄膜-硅三层结构被制备并进行了深入研究。这种具有纳米级厚度的有源 Ba0.6 Sr0.4 TiO3 薄膜混合超材料，由于铁电薄膜和硅衬底之间的电载流子输运，实现了高达 ≈79%的传输对比度。该工作极大地提高了铁电基器件在太赫兹波段的低调制率，这是该领域多年来尚未解决的一个主要问题。所提出的 BST 超材料有望为太赫兹技术开发高性能的实际光子器件。
