Researchers from the Laboratory of Applied Physics and Materials Science in the Division of Engineering and Applied Science at Caltech, suggest that such technology could be used to design spacecraft that work with light and that, therefore, could travel to planets outside the Solar system. Scientists have described their theory of propulsion with light in detail in the journal Nature Photonics.
Physicists have previously used optical tweezers, fine tuning lasers, to trap and manipulate nanoparticles. Researchers have also used light to power small engines. But they have also struggled to scale these technologies, something complicated, because at present they only work with very very small objects and also very small distances.
"You can levitate a ping pong ball using a constant flow of air from a hair dryer," said Ognjen Ilic, Caltech postdoctoral researcher, in a press release. "But it would not work if the ping pong ball were too big, or if it was too far from the hair dryer, etc."
In the new work, scientists claim to have developed a technique to propel large objects using only light.
The researchers designed special nanoscale surface patterns to interact with the laser beam and reorient the propelled object so that it is trapped in the photon stream. The technology does not require a highly focused laser beam. As such, the light source can be millions of kilometers away.
"We have devised a method that could levitate macroscopic objects," said Harry Atwater, leader of the work. "There is an audaciously interesting application to use this technique as a means to propel a new generation of spacecraft, we are far from doing it, but we are in the process of testing the principles."
In their article on the new theory of propulsion, the authors suggest that spacecraft covered with nanoscale patterns could be powered by a laser on Earth, freeing it from the need for heavy fuel. The ship could then -potentially- reach relativistic speeds and visit other stars and planetary systems.
But before the technology is used to accelerate spacecraft, the theory of propulsion to light could, according to Atwater, accelerate the manufacture of small objects such as circuit boards.
Although the theory has not yet been tested in the real world, researchers say that if it develops, it could send a spacecraft to the nearest star outside our solar system in just 20 years.
