Switches made of atoms are changing the future of computing!

Imagine a light switch, just a few atoms in size, that releases photons one by one. These quantum switches, or transmitters, are key building blocks of future technologies: quantum computers, secure communication networks, and sensitive sensors.

For years, scientists have tried to understand and control these phenomena. But new research by American experts has shown how single-photon sources in ultrathin materials can be identified and engineered with atomic precision.

The emitters generate single photons on demand. A capability that is essential for the complete control of light and information. The problem has always been that the atomic defects they cause are extremely small and difficult to observe. Jianguo Wen of Argonne National Laboratory explained: “The optical behavior of quantum emitters is determined by their atomic structure, which is very difficult to see directly.”

The researchers focused on hexagonal boron nitride, a crystal just a few atoms thick. Using the QuEEN-M instrument, they combined atomic-scale imaging with cathodoluminescence spectroscopy, allowing them to directly correlate light emission to specific defects.

They also discovered that twisting the boron nitride layer at specific angles creates “twisted interfaces” that amplify the signal by up to 120 times. This allowed the emitters to be located with a precision of less than 10 nanometers. A key discovery was the blue emitter, which turned out to be a carbon dimer, two carbon atoms in a crystal.

Thomas Gage added: “By linking atomic structure to light, we have opened the door to the precise engineering of quantum emitters on demand.”

This represents a shift from discovery to design. Precisely positioned single-photon sources are key to building scalable quantum devices that process data faster, transmit it securely, and amplify signals with minimal loss.

Despite the progress, the method requires highly specialized microscopes, which limits mass production. Future research will focus on greater scalability and understanding how different atomic structures affect photons.