Professor uses laser for record-breaking particle pull
ECU physics professor Yong-Qing Li and students in his lab have successfully pulled—not pushed—a particle for 10 meters, a distance 10 times greater than earlier experiments.
“The normal way of thinking is the laser will push the particle away due to the laser’s oscillation or the pressure,” Li said. “But what we’re doing here is … the particle will be pulled toward the laser beam.”
The idea of pulling particles with a laser, rather than pushing them, opens up new theoretical possibilities, Li said. If it can be achieved over longer distances, particles from space could be pulled in and captured for analysis. It might even be possible to lift particles from the surface of a planet without a landing craft.
The experiment relies on the principle of photophoresis, in which small, suspended particles migrate when illuminated by an intense beam of light. In Li’s laser lab, the particle is inside a glass tube with slightly reduced air pressure.
The particle absorbs energy from the laser and becomes hotter than the surrounding molecules, and collisions with those molecules change the momentum of the particle.
“This technology may open up a wide range of applications, but we don’t know yet,” Li said.