New twisting technique gives scientists unprecedented control of quantum light Researchers use twisted hBN layers to significantly tune quantum light sources for future quantum devices. Scientists have discovered a new way to control quantum light sources by twisting atomically thin layers of a material known as hexagonal boron nitride (hBN), a breakthrough that could help bring quantum technologies closer to practical use. Researchers from the University of Technology Sydney found that rotating and restacking layers of hBN can significantly alter the color and wavelength of light emitted by quantum emitters embedded within the material. Quantum emitters are tiny light sources that can produce single photons, making them important building blocks for future quantum computers, secure communication networks, and highly sensitive sensors. While scientists have been able to detect and study these emitters, controlling them has remained a major challenge. The team says its approach offers a new way to tune these light sources by exploiting the unique layered structure of hBN, a material that can be repeatedly separated, twisted, and reassembled. Twisting light into control Lead author Dr. Angus Gale said the findings provide researchers with a new tool for manipulating quantum emitters. “You can measure these quantum emitters and see that they exist, but it’s hard to make them work in practice. This gives us a lever to get closer to that – a step towards the realisation of quantum technologies,” said Dr Gale. In experiments, the researchers were able to produce a significant shift in the emitted light by changing the twist angle between layers. Unlike many studies where materials are assembled once and left unchanged, the team repeatedly picked up, twisted, and restacked the layers while continuing to modify the optical properties. “We’re leveraging the fact that this material, hexagonal boron nitride (hBN), is layered. We can