A negative reflecting mirror converts a wave of positive phase velocity into its negative counterpart and vice versa. Whatever the complexity of the propagation medium, the negatively reflected wave field focuses back towards the initial source location, thereby mimicking a phase conjugation operation while being a fully passive process. In this paper, we experimentally demonstrate this phenomenon with elastic waves in a 2D billiard and in a disordered plate by means of laser interferometry. These proof-of-concept experiments show that negative reflection can be a tool of choice for the control and focusing of waves in complex environments.

翻译：反向反射镜将正相速度波变成负相,反之亦然。不管传播介质的复杂性如何,反向反射波场重回原始源位置,从而在完全被动的进程中模仿阶段共振操作。在本文中,我们实验性地用激光干涉测量法,用2D烟囱中的弹性波和有障碍的板块来证明这种现象。这些概念验证实验显示,负反射可能是复杂环境中波的控制和聚焦的首选工具。