Physicists at the California Institute of Technology have designed a method that theoretically could levitate and propel objects using only light waves.

The team believes that the method would lead to the development of a light-powered spacecraft that can travel to the nearest planet outside of the solar system.

The method is described in a paper that appears in the journal Nature Photonics.

Light-Propelled Objects

Decades ago, scientists developed the so-called optical tweezers to move and manipulate objects using the radiative pressure of a focused beam of laser light. However, optical tweezers can only be used to levitate very small objects like nanoparticles, and across very short distances.

"One can levitate a ping pong ball using a steady stream of air from a hair dryer," explained Ognjen Ilic, a postdoctoral scholar at Caltech and the co-author of the study. "But it wouldn't work if the ping pong ball were too big, or if it were too far away from the hair dryer, and so on."

Since then, scientists have struggled to scale the technology, but a group of physicists at Caltech claims that they have figured out a way that could levitate and propel larger objects using light. According to their research, the key is to create a specific nanoscale pattern on the surface of the object that will interact with light.

Instead of using a highly focused laser to manipulate the object, the pattern will "encode" its own stability, moving upright when perturbed so it stays in the stream of photons. Moreover, the source of light can be placed millions of miles away.

Future Of Spaceflight

The researchers are still in the process of testing their methods. They could, however, foresee that the study could one day lead to the development of future spacecraft that can travel outside the solar system and beyond.

The method will enable spacecraft that can be propelled by a laser on Earth. Without the need to carry heavy fuel, the researchers believe that the spacecraft could run at very high and potentially reach relativistic speeds to visit other planetary systems.

There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft," said Harry Atwater, a professor of applied physics and material science at Caltech and the co-author of the study.

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