Two-dimensional optical beam-steering with applications in LiDAR, projection, imaging, and communication is performed using either a 2-D optical phased array (OPA) with per-element optical phase control or a 1-D OPA with a combination of phase control and wavelength tuning. The former typically suffers from a high power consumption and a large element-spacing, and the latter requires a highly tunable laser and is incompatible with certain 2-D beam-steering applications such as communication. In either case, achieving subwavelength element-spacing is challenging due to the large size of devices compared to the operation wavelength. Here, we report a single-wavelength multilayer 2-D OPA, where a beam is formed through near-field interference of waves emitted from array elements on each layer. Vertically aligned tilted optical nanoantennas, 3-D optical signal distribution, and off-aperture phase control enable the realization of a record element-pitch of 3 μm. The 64-element 2-D OPA achieves a steering range of 23° using only 16 phase shifters.

中文翻译：

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具有孔径相位调整的相干多层光子纳米天线阵列

二维光束控制在 LiDAR、投影、成像和通信中的应用是使用具有每个元件光学相位控制的 2-D 光学相控阵 (OPA) 或具有相位组合的 1-D OPA 来执行的控制和波长调谐。前者通常具有高功耗和大元件间距的问题，而后者需要高度可调的激光器，并且与某些二维光束控制应用（如通信）不兼容。在任何一种情况下，由于与工作波长相比器件尺寸较大，实现亚波长元件间距都具有挑战性。在这里，我们报告了一种单波长多层二维 OPA，其中光束是通过每层阵列元件发射的波的近场干涉形成的。垂直排列的倾斜光学纳米天线，3-D 光信号分配和孔径外相位控制能够实现 3 μm 的记录元件间距。64 元件 2-D OPA 仅使用 16 个移相器即可实现 23° 的转向范围。