Sun Hao, Sun Tangyou, Song Qianju, Bian Liang, Yi Zao, Zhang Jianguo, Hao Zhiqiang, Tang Chaojun, Wu Pinghui, Zeng Qingdong
School of Mathematics and Science, Joint Laboratory for Extreme Conditions Matter Properties, The State Key Laboratory of Environment-Friendly Energy Materials, Tianfu Institute of Research and Innovation, Southwest University of Science and Technology, Mianyang 621010, China.
Guangxi Key Laboratory of Precision Navigation Technology and Application, Guilin University of Electronic Technology, Guilin 541004, China.
Dalton Trans. 2024 Oct 29;53(42):17299-17307. doi: 10.1039/d4dt02412e.
Terahertz devices play an irreplaceable role in the development of terahertz technology. However, at present, it is difficult for most natural materials to respond in the terahertz band, making the devices made of them perform poorly. In order to realize the diversity and tunability of device functions, we designed a terahertz metamaterial device composed of the thermally-induced phase change material VO. The device structure is composed of a Au bottom layer, a SiO dielectric layer and a VO top layer. Through software simulation, we found that when = 313 K, the device has complete reflection ability in the whole terahertz band. When = 342 K, the average absorptivity is above 95% in the ultra-wide band range of 4.71-9.41 THz, and the absorptivity reaches an amazing 0.99999 at 6.31 THz. Thus, the maximum thermal modulation range of the device is 0.001-0.99999. The Bruggeman effective medium theory clarifies the phase transition characteristics of vanadium dioxide. The Drude model establishes the functional relationship between the conductivity of vanadium dioxide and temperature. The basic principle of high absorption was described using the impedance matching theory. We also drew the electric field intensity diagram during the temperature rise of the device to further confirm the reason for the change in the device performance. In addition, the influence of the absence of different structural layers on the absorptivity was simulated, which reflected the role of each layer structure more intuitively. We also explored the influence of the geometric size of the device on the absorptivity, which provided a certain reference value for practical application. In short, we have designed a tunable terahertz device with simple structure, high absorptivity, and wide absorption bandwidth, which can be used in the fields of energy collection, electromagnetic stealth, and modulation.
太赫兹器件在太赫兹技术的发展中发挥着不可替代的作用。然而，目前大多数天然材料很难在太赫兹波段产生响应，这使得由它们制成的器件性能不佳。为了实现器件功能的多样性和可调性，我们设计了一种由热致相变材料VO组成的太赫兹超材料器件。该器件结构由金底层、二氧化硅介电层和VO顶层组成。通过软件模拟，我们发现当温度T = 313 K时，该器件在整个太赫兹波段具有全反射能力。当T = 342 K时，在4.71 - 9.41 THz的超宽带范围内平均吸收率高于95%，在6.31 THz时吸收率达到惊人的0.99999。因此，该器件的最大热调制范围为0.001 - 0.99999。布鲁格曼有效介质理论阐明了二氧化钒的相变特性。德鲁德模型建立了二氧化钒电导率与温度之间的函数关系。利用阻抗匹配理论描述了高吸收的基本原理。我们还绘制了器件升温过程中的电场强度图，以进一步确认器件性能变化的原因。此外，模拟了不同结构层缺失对吸收率的影响，更直观地反映了各层结构的作用。我们还探讨了器件几何尺寸对吸收率的影响，为实际应用提供了一定的参考价值。简而言之，我们设计了一种结构简单、吸收率高、吸收带宽宽的可调谐太赫兹器件，可用于能量收集、电磁隐身和调制等领域。
