Researchers from China have developed a laser-based tractor beam that can be used to move larger objects in the macroscopic range. In the future, technology could move vehicles on Mars.
Qingdao (China). Physics has been working on moving small objects with light for a long time. In 2010, for example, scientists at the Australian National University in Canberra manipulated a laser beam in such a way that it looked like a tractor beam. At that time, however, Andrei Rode’s team only succeeded in transporting the smallest particles in the microscopic range.
According to a publication in the specialist journal Optics Express, researchers at Qingdao University of Science and Technology (QUST) in China have now developed a laser- based tractor beam that can also be used to move larger objects in the macroscopic range. As Lei Wang explains, this is possible because the attraction to light has a much larger amplitude.
“In earlier studies, the light pulling force was too low to pull a macroscopic object. In our new approach, the light attraction has a much larger amplitude. In fact, it is more than three orders of magnitude greater than the light pressure used to propel a solar sail that uses the momentum of photons to exert a small amount of thrust.”
Pendulum moved with laser light
In the laboratory, the researchers succeeded in using the tractor beam of laser light to attract a pendulum about five centimeters long. To do this, they aimed the laser at the pendulum, which then visibly moved in the direction of the light.
“We found that the pulling force was more than three orders of magnitude larger than the light pressure. In addition, the laser draw is repeatable and the power can be adjusted by changing the laser power. Our work shows that flexible light manipulation of a macroscopic object is possible when the interactions between the light, the object, and the medium are carefully controlled. It also shows how complex the interactions between lasers and matter are and that many phenomena are still far from being understood at both the macro and micro levels.”
Larger objects cannot be moved with the current tractor beam. In addition, the technology only works under limited conditions in the laboratory.
Pendulum made of graphene-silica composite structure
The pendulum used consists of a graphene-silica composite structure. When this is illuminated with the laser, a reverse temperature difference occurs. As a result, the back becomes hotter than the side hit by the laser. As a result, the gas molecules on the back of the pendulum receive more energy and turn towards the laser. However, this effect only occurs in an inert gas atmosphere, the pressure of which is significantly lower than the pressure of the earth’s atmosphere.
However, according to Earth’s atmosphere, the atmospheric conditions on Mars are similar to the conditions of the experiment. According to him, it is therefore conceivable that a tractor beam could move vehicles on the red planet in the future.
“Our technique enables long-distance non-contact dragging, which can be useful for various scientific experiments. The rarefied gas environment we used to demonstrate the technique is similar to conditions on Mars. Therefore, one day it may have the potential to manipulate vehicles or aircraft on Mars.”