Non-mechanical beam steering for large field of regard global shutter flash LiDAR

Abstract

Global Shutter Flash Lidar (GSFL) is a powerful technology for a host of 3D ranging applications. GSFL generates real-time organized point clouds without motion distortion, which makes it an attractive technology for applications involving moving targets such as remote sensing, guidance navigation and control (GNC), and space situational awareness. In contrast to scanning lidar modalities, the field of view of GSFL is fixed, requiring an external gimbal in order to extend the field of regard without degrading the LIDAR range performance. To overcome this challenge, Advanced Scientific Concepts LLC has developed a GSFL that incorporates Liquid Crystal Polarization Gratings (LCPG) to steer the field of view of the GSFL, resulting in an increased field of regard. Passive LCPGs are thin birefringent solid films that steer light to one of two deflection angles, depending on the polarization handedness of the circularly polarized input light. Electrically variable liquid crystal wave plates included in the stack enable control of polarization handedness to select the desired steering angle at each LCPG. Not only does this result in a step and stare scanner that is simple to control and does not introduce motion blur, but it is also ideal for platforms that have low SWaP requirements. Here we present the operational concepts of the non-mechanical beam steering and quantify the effects of the LCPGs on the GSFL performance.