Self-driving cars often use LiDAR – think of it as radar that uses beams of light. One limitation of current systems is that they need some way to scan the light source around, and that means moving parts. Researchers at the University of Washington have created a laser on a chip that uses sound waves to bend the laser, physically avoiding moving parts. the paper Behind the paywall, but the university has Summary posterYou can also find an overview of [Geekwire].
The resulting IC uses surface sound waves and can image objects over 100 feet away. We imagine this could be useful for other applications like 3D scanning as well. The system weighs less than a traditional setup, too, so this will be useful in drones and similar applications.
The high-frequency acoustic pulses create phonons that deflect the photons in the laser beam. By changing the frequency of the pulses, the beam will sweep through a 20° field of view. Phonons are similar to a diffraction grating. They change not only the direction of the beam, but also its wavelength.
This effect simplifies receiver setup. When the laser energy returns to the receiver, the measured wavelength informs the receiver of the angle corresponding to the transmitted beam. For the system to be practical, it needs a larger scale, and this is due to a system efficiency of about 5%. Getting to 300 meters — a number that would make it practical for self-driving cars — would require 50 percent efficiency, something the team believes they will soon achieve.
LiDAR is one way you can measure the altitude of your drone. It is also important for the next knife throwing machine.
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