The concept of slow light could expedite development of compact, easy-to-use LiDAR 3D sensors in autonomous vehicles, robots and drones, security systems and other applications.
A team from Yokohama National University in Japan published their results in the Optica, a journal published by The Optical Society.
Current-generation LiDAR sensors typically comprise a laser source; a photodetector, which converts light into current; and an optical beam steering device, which directs the light into the proper location. "Currently, existing optical beam steering devices all use some kind of mechanics, such as rotary mirrors," added Toshihiko Baba, paper author and professor in the Department of Electrical and Computer Engineering at Yokohama National University. "It all becomes unstable, particularly in mobile devices, hampering the wide range of applications."
In recent years, according to Baba, more engineers have turned toward optical phased arrays, which direct the optical beam without mechanical parts.
But Baba said, “Such an approach can become complicated due to the sheer number of optical antenna required, as well as the time needed to calibrate each piece.
"In our study, we employed another approach, what we call 'slow light," Baba said. The researchers used a special waveguide "photonic crystal," which is aimed through a silicon-etched medium. Light is slowed down and emitted to the free space when forced to interact with the photonic crystal.
The resulting device is compact, free of moving mechanics, setting the stage for a solid-state LiDAR. Such a device is considered smaller, cheaper to make and more resilient, especially in mobile applications such as autonomous vehicles.
Baba and his team next plan to more fully demonstrate the potential of a solid-state LiDAR, as well as work on improving its performance with the ultimate goal of commercializing the device.