Light detection and ranging (LiDAR) is a key technology for smart mobility of robots, agricultural and construction machines, and autonomous vehicles. However, current LiDAR systems often rely on semiconductor lasers with low-quality, large-divergence, and asymmetric beams, requiring high-precision integration of complicated lens systems to reshape the beam. Also, due to the broad linewidth and the large temperature dependence of their lasing spectrum, a bandpass filter with broad bandwidth must be used in front of the detector, so the detected signal is affected by noise from background light such as sunlight. These critical issues limit the performance, compactness, affordability, and reliability of the LiDAR systems. Photonic-crystal surface-emitting lasers (PCSELs) have attracted much attention as novel semiconductor lasers that can solve the issues of conventional semiconductor lasers owing to their capability of high-quality, very-narrow-divergence, and symmetric beam operation supported by broad-area band-edge resonance in their two-dimensional photonic crystal. In this paper, we show the progress and the state of the art of broad-area coherent PCSELs and their application to a time-of-flight (ToF) LiDAR system. We first review the progress of PCSELs made so far. Next, we show recent progress based on PCSELs with a double-lattice structure that enables higher-power and narrower-divergence operation while keeping a symmetric beam shape. By optimizing the double-lattice photonic crystal and the reflective properties of a backside distributed Bragg reflector (DBR), we achieve a high peak power of 10 W while maintaining a nearly diffraction-limited beam divergence of ∼0.1 (FWHM) from a 500 m diameter resonator. Using this PCSEL, we construct a LiDAR system that uses no external lens system in its light source and demonstrate highly spatially resolved ToF sensing (measurement range of ∼20 m), which is appropriate for autonomous robots and factory automation.

光探测和测距 (LiDAR) 是机器人、农业和建筑机械以及自动驾驶汽车智能移动的关键技术。然而，目前的激光雷达系统往往依赖于低质量、大发散和不对称光束的半导体激光器，需要复杂的透镜系统的高精度集成来重塑光束。此外，由于其激光光谱的宽线宽和大的温度依赖性，必须在检测器前面使用具有宽带宽的带通滤波器，因此检测到的信号会受到来自背景光（例如太阳光）的噪声的影响。这些关键问题限制了 LiDAR 系统的性能、紧凑性、可负担性和可靠性。光子晶体表面发射激光器 (PCSEL) 作为一种新型半导体激光器，由于其高质量、极窄发散和对称光束操作的能力，可以解决传统半导体激光器的问题，因此受到广泛关注。二维光子晶体中的区域带边共振。在本文中，我们展示了广域相干 PCSEL 的进展和最新技术及其在飞行时间 (ToF) 激光雷达系统中的应用。我们首先回顾了迄今为止 PCSEL 的进展。接下来，我们展示了基于具有双晶格结构的 PCSEL 的最新进展，该结构可在保持对称光束形状的同时实现更高功率和更窄发散的操作。m 直径的谐振器。使用该 PCSEL，我们构建了一个 LiDAR 系统，该系统在其光源中不使用外部透镜系统，并展示了高度空间分辨率的 ToF 传感（测量范围约为 20 m），适用于自主机器人和工厂自动化。