Mechanical Engineering Department, Northwestern University, Evanston, Illinois 60208, USA.
Sci Rep. 2011;1:78. doi: 10.1038/srep00078. Epub 2011 Sep 1.
The invisibility cloak has been a long-standing dream for many researchers over the decades. Using transformation optics, a three-dimensional (3D) object is perceived as having a reduced number of dimensions, making it "undetectable" judging from the scattered field12345. Despite successful experimental demonstration at microwave and optical frequencies6789101112, the spectroscopically important Terahertz (THz) domain13141516 remains unexplored due to difficulties in fabricating cloaking devices that are optically large in all three dimensions. Here, we report the first experimental demonstration of a 3D THz cloaking device fabricated using a scalable Projection Microstereolithography process. The cloak operates at a broad frequency range between 0.3 and 0.6 THz, and is placed over an α-lactose monohydrate absorber with rectangular shape. Characterized using angular-resolved reflection THz time-domain spectroscopy (THz-TDS), the results indicate that the THz invisibility cloak has successfully concealed both the geometrical and spectroscopic signatures of the absorber, making it undetectable to the observer.
几十年来，隐形斗篷一直是许多研究人员的长期梦想。利用变换光学，三维（3D）物体被感知为具有减少的维度数，使得从散射场来看“不可检测”12345。尽管在微波和光学频率上已经成功进行了实验演示6789101112，但由于在所有三个维度上制造光学尺寸较大的隐形斗篷设备存在困难，光谱上重要的太赫兹（THz）域13141516仍然未被探索。在这里，我们报告了第一个使用可扩展的投影微立体光刻工艺制造的 3D THz 隐形斗篷设备的实验演示。该斗篷在 0.3 到 0.6 THz 的宽频范围内运行，并且放置在具有矩形形状的α-乳糖一水合物吸收体上。使用角度分辨反射太赫兹时域光谱（THz-TDS）进行表征，结果表明，THz 隐形斗篷成功地隐藏了吸收体的几何和光谱特征，使其对观察者不可检测。
