CATENAA, Sunday, November 16, 2025- Researchers have broken the symmetry barrier of light, generating both even and odd terahertz harmonics with exotic quantum materials, a development that could advance wireless communication and quantum technologies.
The team, led by Professor Miriam Serena Vitiello, used topological insulators, materials that conduct along their surfaces but act as insulators internally, combined with nanostructures called split ring resonators to amplify incoming light.
This allowed them to produce high-order harmonic generation (HHG) across previously inaccessible terahertz (THz) frequencies. Their results appear in Light: Science and Applications.
Traditional materials like graphene are limited to producing odd harmonics, leaving gaps in the electromagnetic spectrum. The researchers demonstrated frequency up-conversion from 6.4 THz (even) to 9.7 THz (odd), showing that both the symmetrical bulk and asymmetrical surfaces of topological insulators contribute to light generation.
This provides a practical demonstration of the interplay between material symmetry and light behavior at the nanoscale.
The findings pave the way for compact, tunable terahertz sources, ultrafast sensors, and advanced optoelectronic devices. By controlling harmonic generation in quantum materials, engineers could create smaller, more efficient devices for high-speed wireless communication, medical imaging, and quantum computing.
This breakthrough confirms long-standing theoretical predictions and highlights the potential of quantum materials to manipulate light in ways previously thought impossible, moving the field closer to real-world applications.
