And, potentially, a new path to advanced devices for sensing, telecommunications and more

University of Michigan researchers have built a device that controls the flow of electrons through a semiconductor using only laser light, with no electrical power required — a demonstration of a long-predicted phenomenon known as the “electron lighthouse” effect.

By rotating the polarization of two phase-coherent optical fields of different colors, the team showed that electrons can be made to flow in a narrow, steerable beam rather than simply being switched on or off. The effect arises from quantum interference between different pathways by which electrons absorb light.

Doctoral student Yiming Gong helped lead the project, which was built at the University of Michigan’s Lurie Nanofabrication Facility, under senior author Steven Cundiff, a U-M physicist. The “electron lighthouse” effect itself was predicted years earlier by collaborator J.E. Sipe of the University of Toronto.

Kai Wang, a former postdoctoral researcher in Cundiff’s lab now at Sun Yat-Sen University in China, provided additional guidance on the project, which was federally supported by the National Science Foundation.

Because the technique steers electron flow using only light, with no applied voltage, the researchers see potential applications in sensing, telecommunications, and other advanced devices that could benefit from light-controlled, power-free electron steering.

Journal: Physical Review Letters
Article Title: Directional Photocurrent Generated by Quantum Interference Control
Publication Date: 16-Jul-2026

Source: EurekAlert