Deng Zi-Lan, Tu Qing-An, Wang Yujie, Wang Zhi-Qiang, Shi Tan, Feng Ziwei, Qiao Xiao-Chen, Wang Guo Ping, Xiao Shumin, Li Xiangping
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.
Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
Adv Mater. 2021 Oct;33(43):e2103472. doi: 10.1002/adma.202103472. Epub 2021 Aug 31.
Malus' law regulating the intensity of light when passed through a polarizer, forms the solid basis for image steganography based on orthogonal polarizations of light to convey hidden information without adverse perceptions, which underpins important practices in information encryptions, anti-counterfeitings, and security labels. Unfortunately, the restriction to orthogonal states being taken for granted in the common perceptions fails to advance cryptoinformation to upgraded levels of security. By introducing a vectorial compound metapixel design, arbitrary nonorthogonal polarization multiplexing of independent grayscale images with high fidelity and strong concealment is demonstrated. The Jones matrix treatment of compound metapixels consisting of double atoms with tailored in-plane orientation sum and difference allows point-by-point configuring of both the amplitude and polarization rotations of the output beam in an analytical and linear form. With this, both multiplexing two continuous grayscale images in arbitrary nonorthogonal polarization angles and concealing grayscale image on another in an arbitrary disclosure angle window are experimentally demonstrated in the visible TiO metasurface platform. The methods shed new light on multifarious metaoptics by harnessing the new degree of freedom and unlock the full potential of metasurface polarization optics.
马吕斯定律规定了光通过偏振器时的光强，它构成了基于光的正交偏振来传输隐藏信息且无不良感知的图像隐写术的坚实基础，这是信息加密、防伪和安全标签等重要实践的基础。不幸的是，在通常认知中被视为理所当然的对正交状态的限制，无法将加密信息提升到更高的安全级别。通过引入矢量复合元像素设计，展示了具有高保真度和强隐蔽性的独立灰度图像的任意非正交偏振复用。对由具有定制面内取向和与差的双原子组成的复合元像素进行琼斯矩阵处理，能够以解析和线性形式逐点配置输出光束的幅度和偏振旋转。据此，在可见的二氧化钛超表面平台上通过实验证明了在任意非正交偏振角度复用两个连续灰度图像以及在任意公开角度窗口中在另一个图像上隐藏灰度图像。这些方法通过利用新的自由度为多样的超光学带来了新的启示，并释放了超表面偏振光学的全部潜力。
