Optics for LIDAR and Sensing

LiDAR is an acronym for Light Detection and Ranging. In LiDAR, near-infrared light is transmitted from a source and reflected from objects into a scene to create a 3D map of the environment. While light travels at 300,000 km per second, measuring the time it takes for beams to return after hitting the object provides information on the environment in which the LiDAR is operating. Based on the information from the receiver, a LiDAR system creates a point cloud that looks like a shadow and reflects the object’s shape and size. 

While the main function of LiDAR is to measure the distance to an object, it has many other applications. The development of LiDAR was originally utilized as a survey technique for measuring topography, buildings, and forestry structures.  In robotics, LiDAR maneuvers the robot around obstacles, and in agriculture, it monitors crop growth and can even detect different types of insects and their movement. Today, however, autonomous vehicles are its most notable application. There are several sophisticated systems in vehicles that rely on precision optics to provide essential information on objects, hazards, and obstructions.  

Today's modern vehicles also use a variety of other optics in rear and front-facing cameras. There is no question that vehicles today are smarter and have more safety measures thanks to sensing platforms. The debate continues whether LiDAR is a better sensing solution for autonomous vehicles as opposed to Tesla founder, Elon Musk, who has previously stated his disdain for LiDAR. In one camp, Tesla vehicles lean on a neural network that consists of eight cameras and twelve ultrasonic sensors to capture information from its surroundings. On the other side of the debate, LiDAR technology is quickly becoming smaller, more cost-effective and better at collecting data. Big industry names like Schott have numerous LiDAR platforms and Google is a big user of LiDAR technology for autonomous vehicles.   

Two widely used LIDAR architectures are scanning and non-scanning systems (also known as flash). In a flash system, a laser beam is emitted from the source and then diffused by an optical element to irradiate over a wide angle in a flash. The reflected light is then imaged onto a detector array, and the field of view is calculated for each element in the detector. 

The second architecture, a scanning system, uses rotational aspects to gather information in a wider field of view. A MEMS-based scanning system incorporates a micro-mirror or rotating prism to observe the field of view. The rotating mirror directs the laser, and then the reflected light is detected by a single photodetector calculating the field of view. These systems can be more accurate than flash systems, and allow for longer detecting ranges, but are bulkier, more complex and expensive. A more widely used method is a polygon laser system where a mirror polygon spins at a high rate of speed sending the laser into different positions. Polygon scanners have a higher scan rate, a longer range, and higher resolutions for airborne, mobile, and maritime LIDAR systems.  

From an optical manufacturer's perspective, we help produce many of the components for LiDAR and other sensing applications whether for private industry or for military/defense purposes. We specialize in super polishing for both plano and spherical optics to enable customers to achieve tighter tolerances. To learn more, get in touch with us today for your next optical advancement at sales@EscoOptics.com.