The green beam can pull the glass beads dozens of centimeters, the longest distance the tractor beam has ever had.
No matter what sci-fi would suggest, when light illuminates an object, it is difficult to make the object move in the opposite direction.
Light scattering of objects provides a driving force.
National University of Australia physicist Wieslaw krolikoski and his team use air temperature and pressure to counter this effect and create pull force.
They light up 50micrometer-wide gold-
Coat the glass beads with a hollow green laser beam and then adjust the direction of the polarization of the light or the vibration of the light.
When the researchers point the polarization direction to the center of the beam, the target bead moves forward, away from the light source.
But when they make the polarization tangent to the beam, the light heats the back of the bead, which also reduces the pressure on the surrounding air.