Calgary quantum researchers demonstrate light conversion in diamonds

University of Calgary researchers showed second-harmonic generation in diamond by using tiny crystal defects, and the results were published in December 2025.

Researchers at the University of Calgary's Quantum Nanophotonics Lab reported a discovery about diamond optical properties in a paper published in December 2025. They demonstrated second-harmonic generation, the conversion of one colour of light to another, in diamond by using tiny defects in the crystal lattice. Diamonds were previously thought too symmetric to support that effect. The team said they can control how strongly the effect appears. Key findings: - The lab reported second-harmonic generation in diamond, described in a paper published in December 2025. - The effect was enabled by leveraging tiny defects in the diamond crystal structure. - Prior understanding held that diamond symmetry prevented such wavelength conversion. - Researchers noted diamond's ability to handle high laser power and suggested the work could, in principle, enable optical switches, lasers, or modulators that tolerate higher power. - Practical examples mentioned in the report include data centres, high-powered laser fabrication, and optical processing. - The team first observed the phenomenon in experiments at the end of 2023 and through 2024, and reported reaching a final model by early 2025. Summary: The discovery indicates diamonds can support controlled wavelength conversion when engineered defects are present, which could open new directions in quantum nanophotonics. The research was published in December 2025 and builds on experiments dating back to late 2023. Undetermined at this time.