DARPA achieves on-chip LIDAR, advanced light-bending laser scanning

Autonomous navigation, precise targeting and communication, chemical-biological sensing, and other imperative military capabilities all rely on LIDAR (radar that uses light waves to sweep for data) to perform high resolution scanning, but LIDAR, with its expensive bulky mechanical assemblage, is impractical for widespread adoption into the consumer sector. But now, DARPA is developing an on-chip optical phased array, or a miniaturized solid-state solution free from the confines of gimbaled mounts, servos, and motors; essentially, a portable, low-cost solution.

In short, this latest solution bents light on a microchip, meaning, DARPA has demonstrated solid-state optical phased array technology on an integrated circuit. For those unfamiliar, phased array optics (PAO) technology is based on using sub-wavelength phase and amplitude modulators to control the phase of light waves transmitting (or reflecting) from a two-dimensional surfaces.

The concept has been around since WWII in the form of phased radar arrays and is demonstrated in the beamforming used in our mobile communications or maritime radar, but insofar the technology was incapable of apply the same principles in manipulating the visible parts electromagnetic spectrum because of technological limitations. Putting this into perspective, the radio waves detected by radar are the range between 1 millimeter and 100 kilometers with frequencies in the kHz to GHz, but visible light exhibits wavelengths in the range of 400 to 700 nanometers with many hundreds of THz in frequency.

Previously attempted solutions such as LIDAR (a play on words of light and radar) and liquid-crystal-based spatial light modulators suffer from being slow, costly, and of limited efficiency. DARPA’s latest achievement controls light using a solid-state approach, and because it’s based on an IC, the solution is both practical to manufacture through standard semiconductor processing, and scalable. 

Codenamed SWEEPER, Short-range Wide-field-of-view Extremely agile Electronically steered Photonic EmitteR, the exact technical specs remain classified, but the agency claims that the tech can sweep a laser back and forth at a rate of more than 100,000 times per second, equivalent to 10,000 faster than contemporary mechanical systems deemed state-of-the-art. Furthermore, SWEEPER can precisely steer a laser across a 51° arc, the widest field of view ever achieved by a system-on-chip optical scanning device.

What does this actually mean? SWEEPER’s fruition will lead to drastically enhanced sensors and communication systems for autonomous vehicles, robots, mobile infrastructure, of course, with enhanced battlefield scanning. Basically, an improved, low-cost, miniaturized version of LIDAR.

Source: ExtremeTech via DARPA