近日，韩国浦项科技大学的Seung-Hwan Baek&Junsuk Rho及其研究团队取得一项新进展。经过不懈努力，他们实现具有习得超表面的360°结构光。相关研究成果已于2024年6月11日在国际知名学术期刊《自然—光子学》上发表。

该研究团队展示了360°结构光，由习得超表面驱动。研究人员提出了一个可微框架，包括一个计算效率高的180°波传播模型和一个特定任务的重构器，并利用了超表面的透射和反射通道。研究人员利用可微框架内的一阶优化器，优化了超表面设计，从而实现了360°结构光。这项技术被广泛应用于全息光投影和三维成像中。

具体来说，研究团队展示了首个复杂的360°光投影图案，并且他们的传播模型在计算效率上比传统的瑞利-索默菲尔德传播方法快达50000倍。在三维成像方面，与启发式结构光技术相比，他们的方法显著提高了深度估计的精度，均方根误差降低了5.09倍。这种360°结构光为机器人、扩展现实系统和人机交互提供了强大的360°成像和显示能力。

据悉，结构光已被证明是三维成像、激光雷达和全息光投影的重要工具。超表面，包括亚波长大小的纳米结构，有利于180°视场结构光，绕过传统光学元件固有的视场限制，如衍射光学元件。然而，由于启发式设计模式(如不考虑最终应用目标的周期点)，现有的超表面促进结构光在下游任务中表现出次优性能。

附：英文原文

Title: 360° structured light with learned metasurfaces

Author: Choi, Eunsue, Kim, Gyeongtae, Yun, Jooyeong, Jeon, Yujin, Rho, Junsuk, Baek, Seung-Hwan

Issue&Volume: 2024-06-11

Abstract: Structured light has proven instrumental in three-dimensional imaging, LiDAR and holographic light projection. Metasurfaces, comprising subwavelength-sized nanostructures, facilitate 180°-field-of-view structured light, circumventing the restricted field of view inherent in traditional optics like diffractive optical elements. However, extant-metasurface-facilitated structured light exhibits sub-optimal performance in downstream tasks, due to heuristic design patterns such as periodic dots that do not consider the objectives of the end application. Here we present 360° structured light, driven by learned metasurfaces. We propose a differentiable framework that encompasses a computationally efficient 180° wave propagation model and a task-specific reconstructor, and exploits both transmission and reflection channels of the metasurface. Leveraging a first-order optimizer within our differentiable framework, we optimize the metasurface design, thereby realizing 360° structured light. We have utilized 360° structured light for holographic light projection and three-dimensional imaging. Specifically, we demonstrate the first 360° light projection of complex patterns, enabled by our propagation model that can be computationally evaluated 50,000× faster than the Rayleigh–Sommerfeld propagation. For three-dimensional imaging, we improve the depth-estimation accuracy by 5.09× in root-mean-square error compared with heuristically designed structured light. Such 360° structured light promises robust 360° imaging and display for robotics, extended-reality systems and human–computer interactions.

DOI: 10.1038/s41566-024-01450-x

Source: https://www.nature.com/articles/s41566-024-01450-x