Earlier scientific studies demonstrated that light could kickstart an electron flow, but the U-M team took that concept further.
How Quantum Interference Shapes the CurrentThe steering mechanism relies on a phenomenon known as quantum interference.
Engineering the “Electron Lighthouse”The concept of an “electron lighthouse” was theoretical until collaborator J.E.
Building a physical device that could demonstrate quantum interference without introducing unwanted stray electrical signals proved to be a major obstacle.
Gong spent considerable time developing a custom fabrication process to bond the necessary semiconductor materials without generating external electrical noise.
A group of scientists from the University of Michigan has created a revolutionary invention that is capable of controlling the flow of electrons through a semiconductor via the use of only laser light without the necessity of electrical energy supply. The discovery was made at Lurie Nanofabrication Facility of U-M and originated in a study of physics, yet it promises practical applications in the realm of optics-electronics interface.
The team of researchers believes that the new technique can revolutionize signal transmission within and between electronics as well as help develop new ways to encode more information in such signals.
Moving Electrons Without Electricity
In conventional electronics, electric fields push electrons through a material, causing them to drift and bump around until they form a current. The new device operates on an entirely different principle: it uses two distinct colors of light to guide electrons in a neat, highly directed flow. By simply rotating the polarization—the directional wiggling of the light waves—the team can steer the resulting electronic current where they want it to go.
Earlier scientific studies demonstrated that light could kickstart an electron flow, but the U-M team took that concept further. Their setup doesn’t just activate the movement; it focuses the electrons into a tight, steerable beam.
How Quantum Interference Shapes the Current
The steering mechanism relies on a phenomenon known as quantum interference. This occurs when two light frequencies trigger different absorption routes that lead to the exact same energy state. As the semiconductor absorbs energy in discrete photon packets, its internal electric charge carriers become mobile.
Because two separate routes are driven simultaneously, their interactions resemble overlapping water ripples. Where these microscopic ripples align, they reinforce one another and launch electrons along a specific path. Where they clash, they cancel each other out, suppressing electron movement in all other directions.
Engineering the “Electron Lighthouse”
The concept of an “electron lighthouse” was theoretical until collaborator J.E. Sipe from the University of Toronto predicted it could be built. Bringing that theoretical concept into reality required extensive engineering at U-M’s Lurie Nanofabrication Facility (LNF).
Building a physical device that could demonstrate quantum interference without introducing unwanted stray electrical signals proved to be a major obstacle. Gong spent considerable time developing a custom fabrication process to bond the necessary semiconductor materials without generating external electrical noise.
Gong received additional guidance on the project from Kai Wang, a former postdoctoral researcher in Cundiff’s lab who has since become a professor of electronics and information at Sun Yat-Sen University in China.
Following the success of the project, Gong earned his doctorate from the University of Michigan and transitioned to a career as a machine-learning scientist in Chicago, applying the quantitative and analytical skill set he developed during his physics research to computational modeling.
