Traditional distorting mirrors utilize curved surfaces to produce distorted virtual images, i.e., illusions. Here we propose the concept of flat distorting mirrors (FDMs) based on gradient metasurfaces and investigate the shape, orientation, and position of the virtual images generated by such FDMs through a ray optics approach. The virtual images can be controlled by varying the distribution of the additional wave vector of the metasurface, which manipulates the deflection of the reflected light. We find that the “effective curvature” of the FDM is related to the derivative of the additional wave vector. When the additional wave vector or its derivative is discontinuous at a certain point, the virtual images can be split. This Letter provides a guide for designing FDMs that create illusions without using curved surfaces.

中文翻译：

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通过超表面的平面扭曲镜

传统的扭曲镜利用曲面来产生扭曲的虚拟图像，即幻觉。在这里，我们提出了基于梯度超表面的平面扭曲镜 (FDM) 的概念，并通过射线光学方法研究由此类 FDM 生成的虚拟图像的形状、方向和位置。虚拟图像可以通过改变超表面的附加波矢量的分布来控制，这控制了反射光的偏转。我们发现 FDM 的“有效曲率”与附加波矢量的导数有关。当附加波矢量或其导数在某一点不连续时，虚像就可以分裂。这封信提供了设计 FDM 的指南，该 FDM 无需使用曲面即可产生幻觉。