Researchers at the California Institute of Technology (Caltech) have developed a way to lift and accelerate objects using light alone, creating special nanoscale patterns on their surfaces.
Despite the fact that the work is still purely theoretical, this is a step towards developing a spacecraft that can reach the nearest planet outside the solar system in just 20 years, using only light as fuel. An article describing the study was published in the journal Nature Photonics.
Decades ago, the development of so-called optical tweezers allowed scientists to move and manipulate small objects, such as nanoparticles, using light pressure from a finely tuned beam of laser light. This work led Arthur Ashkin to the 2018 Nobel Prize in Physics. However, optical tweezers can only manipulate very small objects and at extremely short distances.
“A ping-pong ball can be lifted with a constant stream of air from a hair dryer,” explains lead author Ognjen Ilic. "But it wouldn't have worked if the ping-pong ball was too big, or if it was too far from the hair dryer, and so on."
Engineering optical anisotropy for self-stabilizing manipulation / Atwater laboratory.
A beam of light can manipulate objects of various shapes and sizes, from micrometers to meters, according to new research. The key lies in creating special nanoscale patterns on the surface of the object. These structures interact with light in such a way that an object can align itself when exposed to it, creating a restorative moment to stay in the light beam. The object will no longer need precisely focused laser beams, as the patterns on its surface are designed to "encrypt" stability. Moreover, the light source can be millions of kilometers from the object.
“We have developed a method that can lift macroscopic objects,” says Harry Atwater. - This technique can be used in a very interesting way - as a means of accelerating a new generation of spacecraft. We are still far from making it, but we are in the process of testing these principles."
In theory, such a spacecraft could be coated with the necessary nanoscale structures and then accelerated using ground-based laser light. With no fuel on board, it will be able to reach very high, even relativistic, velocities, and possibly even other stars.
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According to Atwater, the technology can be used on Earth to quickly produce much smaller objects like printed circuit boards.
Vladimir Guillen
