Scientists create an “electron lighthouse” with laser light

Researchers at the University of Michigan have developed a semiconductor device that controls electron movement using only laser light. This breakthrough marks the first time scientists have successfully directed an electron flow without the need for an applied electric field or an external power source. By using two colors of light, the team created what they call an electron lighthouse. This device acts like a rotating beam where the direction of the electron current changes based on the polarization of the optical fields.

The mechanism relies on quantum interference, where two different optical absorption pathways reinforce electron movement in one direction while canceling it out in others. Yiming Gong, who led the project during his doctoral studies, managed to fabricate the device at the Lurie Nanofabrication Facility after experimenting with various material recipes. The primary challenge involved eliminating all extraneous electric fields to confirm that the observed current originated entirely from the light source.

While this work began as a test of fundamental physics, the implications for future technology are significant. By mastering the ability to aim currents through light, researchers have opened a path for new applications in advanced sensing, imaging, and telecommunications. This method could eventually change how signals move between electronic components and allow for denser data encoding within hardware.

This experiment confirms a long-standing prediction made by J.E. Sipe of the University of Toronto. The team published their results in Physical Review Letters, demonstrating that light can act as both a switch and a navigational tool for electrons. As hardware continues to shrink in size, the ability to control charge carriers with precision using optical fields provides a promising alternative to traditional power-hungry methods of signal propagation.