Scientists create an “electron lighthouse” with laser light

Researchers at the University of Michigan have reached a new milestone in physics by creating a device that controls electron flow using only laser light. This breakthrough marks the first time scientists have successfully directed electrons through a semiconductor without the need for an external electric field or traditional power sources. By using two distinct colors of light, the team created a mechanism that behaves like a lighthouse, sweeping a beam of electrons across the material with high precision.

The core of this discovery relies on quantum interference. When light hits the semiconductor, it creates specific absorption pathways. By aligning these optical ripples, the researchers cause electrons to travel in one specific direction while canceling movement in others. This level of control allows the team to aim the electron stream by simply rotating the polarization of the incoming light fields.

Steven Cundiff, a lead physicist on the project, explains that this method changes how we approach electron mobility. In typical electronics, charge carriers bounce through materials due to external voltage. In this new device, the light acts as both the trigger and the steering mechanism. This provides a way to move charge with unprecedented accuracy and minimal interference from external fields.

This technology began as a theoretical prediction by J.E. Sipe at the University of Toronto before Yiming Gong transformed the concept into a functioning device at the Lurie Nanofabrication Facility. Building the device required significant trial and error to ensure no extraneous electrical fields influenced the results. The team confirmed that the measured current originated solely from the light interaction.

While this work focuses on fundamental physics, the implications for future technology are clear. The ability to direct electrons with light could improve signal transmission between devices and increase data encoding density. The team plans to investigate how this mechanism might support future applications in sensing, imaging, and telecommunications. This research moves us closer to integrating optical and electronic systems at a base level.