Lidar (Light Detection and Ranging) is a technology that uses laser light to measure distances and create detailed, three-dimensional maps of the surroundings. Lidar illumination systems typically consist of a laser source with a mechanism that steers the beam over the FOV or an array of laser sources that emit over the entire FOV in a single flash.
Flash LiDAR
The latter approach is called flash LiDAR. A common approach is to project a source array onto an object and use a 2D diffractive grating to duplicate that projected image over the full FOV. VCSELs are a good choice, because they can be integrated into 2D arrays with sufficient modulation bandwidth to generate fast, high-power pulses.
LiDAR Receivers
There are many optical design forms that can be used for LiDAR. As part of a LiDAR receiver trade study, I designed a variety of CPC and Fresnel optics. A simple 2-mirror on-axis telescope can also be used.