He Ziqian, Yin Kun, Wu Shin-Tson
College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816, USA.
Light Sci Appl. 2021 Jun 28;10(1):134. doi: 10.1038/s41377-021-00576-9.
Non-mechanical beam steerers with lightweight, compact, high-efficiency, high-precision, and/or large-angle are pivotal for light detection and ranging (LiDAR) of autonomous vehicles, eye-tracking for near-eye displays, microscopy, optical tweezers, and high-precision three-dimensional (3D) printing. However, even the most matured optical phased array can only provide quasi-continuous, efficient beam steering within a small angle range. A telescope module with an angle magnification function can be coupled to enlarge the steering range or precision. But obtaining a compact, low-cost, lightweight, high-quality telescope module with conventional optics remains challenging. Patterned liquid crystal-based planar optical elements offer great design freedom for manipulating the phase profile of light in 2D space. Owing to the advantages of high efficiency, thinness, low cost, easy processing, flexibility, and response to environmental stimuli, a plethora of high-quality optical devices have been demonstrated. Here, a miniature planar telescope mediated by liquid crystal polymers is proposed to offer angle magnification independent of incident spatial location. It consists of two cascaded liquid crystal planar optical elements, each performing a predefined mathematical transformation. By this concept, planar optical elements are fabricated using a new exposure method and assembled into planar telescopes with different magnification factors. Within the incident field range, over 84.6% optical efficiency is achieved with small wavefront distortion. Such a miniature planar telescope shows the potential of cascaded liquid crystal planar optical elements for realizing functionalities that cannot be fulfilled by single optical elements, and enables lightweight, low loss, passive optical transmitters for widespread applications.
具有轻量、紧凑、高效、高精度和/或大角度特性的非机械光束转向器对于自动驾驶车辆的光探测和测距（LiDAR）、近眼显示器的眼动追踪、显微镜、光镊以及高精度三维（3D）打印至关重要。然而，即使是最成熟的光学相控阵也只能在小角度范围内提供准连续、高效的光束转向。可以耦合一个具有角度放大功能的望远镜模块来扩大转向范围或提高精度。但是，用传统光学器件获得一个紧凑、低成本、轻量、高质量的望远镜模块仍然具有挑战性。基于图案化液晶的平面光学元件在二维空间中操纵光的相位分布方面提供了极大的设计自由度。由于具有高效率、薄型、低成本、易于加工、灵活性以及对环境刺激有响应等优点，已经展示了大量高质量的光学器件。在此，提出了一种由液晶聚合物介导的微型平面望远镜，以提供与入射空间位置无关的角度放大。它由两个级联的液晶平面光学元件组成，每个元件执行预定义的数学变换。通过这一概念，使用一种新的曝光方法制造平面光学元件，并将其组装成具有不同放大倍数的平面望远镜。在入射场范围内，实现了超过84.6%的光学效率，且波前畸变很小。这种微型平面望远镜展示了级联液晶平面光学元件实现单光学元件无法完成的功能的潜力，并为广泛应用提供了轻量、低损耗的无源光发射器。
