Lai Weien, Liu Gen, Gou Hanguang, Wu Huizhen, Rahimi-Iman Arash
National Engineering Laboratory of Special Display Technology, National Key Laboratory of Advanced Display Technology, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009, P. R. China.
Department of Physics and Zhejiang Province Key Laboratory of Quantum Technology and Devices, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, P. R. China.
ACS Appl Mater Interfaces. 2022 Sep 28;14(38):43868-43876. doi: 10.1021/acsami.2c10186. Epub 2022 Sep 15.
Omnidirectional broadband terahertz (THz) antireflection (AR) with an actively configurable coating promises the achievement of next-generation efficient and versatile THz components with high performance. We demonstrate a near-infrared (NIR) light-tunable and omnidirectional broadband THz AR coating based on an impedance matching method and composed of a poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/graphene composite film. The omnidirectional broadband properties of the active AR coating can be efficiently achieved by tunable NIR optical excitation of less than 0.27 W·cm, which exhibits omnidirectional suppression of THz-wave reflection for incidence angles from 0 to 70°, concerning the broadband frequency range of 0.1-3.0 THz, with an ultrafast response time of ∼5 ps. Furthermore, we demonstrate that the active AR coating can improve the performance of a reflectance-tunable THz-wave polarization reflector by the elimination of Fabry-Pérot interference. The NIR irradiance-dependent active AR mechanism of the hybrid system is investigated, which demonstrates the essential role of the PEDOT:PSS/graphene layers in promoting the charge separation at the interface and therefore changing the photoconductivity of the composite film to achieve impedance matching under optical excitation. Several crucial advantages of the proposed and proven concept, including the wide-angle range, broad spectral range, flexible tunability, and easier fabrication, may revolutionize the AR strategy at THz frequencies for a wide range of THz applications.
具有主动可配置涂层的全向宽带太赫兹（THz）抗反射（AR）技术有望实现下一代高性能、高效且通用的太赫兹组件。我们展示了一种基于阻抗匹配方法、由聚（3,4 - 乙撑二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）/石墨烯复合膜组成的近红外（NIR）光可调谐全向宽带太赫兹AR涂层。通过小于0.27 W·cm的可调谐近红外光激发，可以有效地实现有源AR涂层的全向宽带特性，该涂层在0.1 - 3.0 THz的宽带频率范围内，对于0至70°的入射角表现出太赫兹波反射的全向抑制，响应时间超快，约为5 ps。此外，我们证明了有源AR涂层可以通过消除法布里 - 珀罗干涉来提高反射率可调太赫兹波偏振反射器的性能。研究了混合系统的近红外辐照度依赖有源AR机制，该机制证明了PEDOT:PSS/石墨烯层在促进界面电荷分离从而改变复合膜的光电导率以在光激发下实现阻抗匹配方面的重要作用。所提出并经证实的概念的几个关键优势，包括宽角度范围、宽光谱范围、灵活可调性和易于制造，可能会彻底改变太赫兹频率下用于广泛太赫兹应用的AR策略。
