Han Chunrui, Parrott Edward P J, Humbert Georges, Crunteanu Aurelian, Pickwell-MacPherson Emma
Department of Electronic Engineering, The Chinese University of Hong Kong Shatin, New Territories, Hong Kong, China.
XLIM Research Institute, University of Limoges, Limoges, France.
Sci Rep. 2017 Oct 5;7(1):12725. doi: 10.1038/s41598-017-13085-w.
Broadband modulation of terahertz (THz) light is experimentally realized through the electrically driven metal-insulator phase transition of vanadium dioxide (VO) in hybrid metal antenna-VO devices. The devices consist of VO active layers and bowtie antenna arrays, such that the electrically driven phase transition can be realized by applying an external voltage between adjacent metal wires extended to a large area array. The modulation depth of the terahertz light can be initially enhanced by the metal wires on top of VO and then improved through the addition of specific bowties in between the wires. As a result, a terahertz wave with a large beam size (~10 mm) can be modulated within the measurable spectral range (0.3-2.5 THz) with a frequency independent modulation depth as high as 0.9, and the minimum amplitude transmission down to 0.06. Moreover, the electrical switch on/off phase transition depends very much on the size of the VO area, indicating that smaller VO regions lead to higher modulation speeds and lower phase transition voltages. With the capabilities in actively tuning the beam size, modulation depth, modulation bandwidth as well as the modulation speed of THz waves, our study paves the way in implementing multifunctional components for terahertz applications.
通过混合金属天线 - 二氧化钒（VO）器件中二氧化钒（VO）的电驱动金属 - 绝缘体相变，在实验上实现了太赫兹（THz）光的宽带调制。这些器件由VO有源层和蝴蝶结天线阵列组成，这样通过在延伸至大面积阵列的相邻金属线之间施加外部电压，就可以实现电驱动相变。太赫兹光的调制深度最初可以通过VO顶部的金属线得到增强，然后通过在金属线之间添加特定的蝴蝶结进一步改善。结果，在可测量的光谱范围（0.3 - 2.5 THz）内，可以调制具有大光束尺寸（约10毫米）的太赫兹波，其频率无关调制深度高达0.9，最小幅度传输低至0.06。此外，电开关的开/关相变非常依赖于VO区域的大小，这表明较小的VO区域会导致更高的调制速度和更低的相变电压。凭借主动调节太赫兹波的光束尺寸、调制深度、调制带宽以及调制速度的能力，我们的研究为实现太赫兹应用的多功能组件铺平了道路。
