n 2015 Quanergy wowed crowds at CES with claims that it had a lidar that steered its laser beam without moving parts. Such a solid-state lidar would be smaller, tougher, and cheaper than the handmade rotating roof towers of Velodyne, then as now the leading lidar company.

It works like this: You break a beam into daughter beams, then delay one of the daughters by passing it through a medium that’s under the influence of some moderator, like an audio or an electrical pulse (Eldada won’t say what moderation he uses). That delay shifts the phase, so that one beam’s peaks and troughs come after those of the other beam, interfering. The interference then constitutes a new beam, one that can be steered by playing with the phase delay.