创新背景

中国古代制作出一种青铜镜，使用它观察自己的影像时是普通的平面镜，阳光直射镜面时，镜面反射的光斑会显示镜子背面的图案，产生透光现象。20世纪初，科学家利用光学和物理学知识解释了其中的奥妙——镜面曲率对光的反射程度不同造成透光现象。

创新过程

加拿大研究人员收到青铜镜透光现象的启发，利用其原理使用液晶制造了一个平面魔法窗。这是一种在光线照射时会反射或产生隐藏图像的透明装置，相关研究成果于2022年5月发表在《光学》期刊上。

创建平面魔法窗使用的是由固态向液态转化过程中存在的取向有序流体，既可以像液体一样流动，又具有固态晶体的分子一样取向有序的液晶。研究使用液晶器件潘查拉特奈姆—贝瑞，利用这一光学器件的原理对液晶进行改造。改变设备中液晶分子的方向，进而人为改变光穿过设备时的逐个像素。改造后的液晶会产生特定的液晶图像，在遇到光线照射时反射出来。

研究人员表示，使用液晶制造魔法窗，将来可以运用于电影、动态艺术或3D显示。这种平面魔法窗在人眼中是完全平坦的，但实际上会根据光线产生轻微变化和任何所需图像。窗面的平滑有利于观察图像距离的扩大，即使离窗很远，也能看到光线在魔窗上产生的图像，这样从不同距离观看也能产生稳定的3D图像。

研究使用相机测试魔法窗的光强度模式。证明强光模式下，窗户会产生可见的图像。且相机与窗户之间的距离发生变化，该图像也能保持稳定。此外，这些设备在用LED光源照明时也会产生图像。

研究人员进一步对魔法窗进行设想实验，希望用该方法制造量子魔板。例如两个魔板可创建纠缠图像，运用于研究量子成像协议。并且，研究人员正在探索用其他方法和材料制造魔窗的可能性，例如使用介电超表面制造魔窗设备可减少其占用空间，增加实用性。

创新关键点

利用液晶制造平面魔法窗增强光学成像应用可能。

Planar magic windows created using liquid crystals may observe images of quantum entanglement

Canadian researchers, inspired by the phenomenon of bronze mirror light transmission, used its principle to create a flat magic window using liquid crystals. This is a transparent device that reflects or produces hidden images when light is illuminated, and the results of the research were published in the journal Optics in May 2022.
 The creation of a planar magic window uses an ordered liquid crystal that is oriented ordered from solid to liquid, which can both flow like a liquid and have molecules with solid crystals oriented to order. The study used the liquid crystal device Panchala Tenem-Berry to modify the liquid crystal using the principle of this optical device. Change the orientation of the liquid crystal molecules in the device, and then artificially change the pixel by pixel as light passes through the device. The modified liquid crystal produces a specific liquid crystal image that is reflected when exposed to light.
The researchers say that the use of liquid crystals to create magic windows can be used in film, dynamic art or 3D displays in the future. This flat magic window is completely flat in the human eye, but actually produces slight variations and any desired images depending on the light. The smoothing of the window is conducive to observing the expansion of the image distance, even if it is far from the window, you can see the image produced by the light on the magic window, so that viewing from different distances can also produce a stable 3D image.
Study the light intensity pattern of the magic window tested using a camera. Proof that in bright light mode, the window produces a visible image. And the distance between the camera and the window changes, the image can also remain stable. In addition, these devices also produce images when illuminated with LED light sources.
The researchers further imagined experiments on the magic window, hoping to use this method to create a quantum magic board. For example, two magic plates can create entangled images for use in the study of quantum imaging protocols. And, researchers are exploring the possibility of making magic windows with other methods and materials, such as the use of dielectric metasurfaces to make magic window devices that reduce their footprint and increase their practicality.

来源：科学日报