A team of Chinese scientists have developed a laser capable of seeing through walls from a kilometre away.
Once relegated to the realm of
science fiction, the significant advancement in quantum electronics may have
applications in everything from defence to autonomous driving.
Developed by a group of University of Science and Technology of China researchers,
the technique is called non-line-of-sight (NLOS), according to a paper published
in Proceedings of the National Academy of Sciences.
The researchers developed the method by setting up a laser emitter in a university
campus room in Shanghai, and a mannequin placed in a downtown flat located
roughly 1 000 meters away.
The device emits a pulsing laser
across the streets of the city and into the room with the mannequin. The pulse
of photons scatter off any walls and surfaces they encounter.
By analysing how the photons interreact with the walls, screen, and mannequin,
the scientists can calculate the mannequin’s position relative to the walls and
screen and draw a rough 3D image of the room and the mannequin, with a
sophisticated algorithm.
The scientists point out that
interpreting the position of the mannequin is possible because the speed of
light is always a constant 299 792 458 meters per second.
To overcome the obvious puzzle distance presented, the laser system was
designed with multiple lenses which prevented stray light from interfering with
its long journey from the campus room to the downtown flatlet.
The algorithm designed to create
a visual representation of the environment was developed with long-range
outdoor travel.
The paper explains that NLOS has a “range three orders of magnitudes
longer” than any existing technology which opens it up to real-world
scenarios.
Wu Cheng, a co-author of the research paper, told the media that NLOS may be
useful in the continuing effort to make safe autonomous driving.
He said road surface and other
rough or sub-optimal surfaces in a street environment would be sufficient to
reflect the light needed for an image to be created, but the development team
would have to overcome the dynamic movement of the self-driving car.
Wu also said NLOS could help law enforcement officials locate hostages or
strategic targets with greater efficiency.
