Continuous and reversible tuning of the properties of optical metasurfaces, as a functionality that would enable a range of device applications, has been a focus of the metasurface research field in recent years. Tuning mechanisms proposed and demonstrated so far have generally relied upon changing the morphology of a metasurface or the intrinsic properties of its constituent materials. Here we introduce, via numerical simulation, an alternative approach to achieve continuous tuning of gradient metasurface response, and illustrate its potential application to the challenge of continuous beam steering, as required for example in LIDAR and machine vision systems. It is based upon the coherent illumination of a silicon nano-pillar metasurface with two counter-propagating beams. Control of the input beams’ relative phase and intensity enables tuning of the individual nano-pillars’ electromagnetic response and thereby the phase gradient of the array, which in turn steers the direction of the output beam continuously over an angular range of approximately 9 degrees.

中文翻译：

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通过介电超表面相位梯度的相干光控制实现连续光束转向

近年来，光学超表面的特性的连续和可逆调整是一种功能，可以实现一系列设备应用，这已成为超表面研究领域的重点。到目前为止，提出和证明的调整机制通常依赖于改变超表面的形态或其组成材料的固有特性。在这里，我们通过数值模拟介绍了实现梯度超表面响应的连续调整的另一种方法，并举例说明了其在连续光束转向挑战中的潜在应用，例如在LIDAR和机器视觉系统中。它基于两个反向传播的光束对硅纳米柱超表面的相干照明。