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Researchers Jiaxin Ye and colleagues published findings in the journal *Diamond and Related Materials* regarding how ultraviolet laser pulses can selectively engineer defects within diamond crystals. The study, titled "Selective engineering of color centers in diamond using ultraviolet nanosecond laser pulses," was released in 2026 with the DOI 10.1016/j.diamond.2026.114126.

The team used single-crystal chemical vapor deposition (CVD) diamond and irradiated specific regions with 266-nanometer ultraviolet laser pulses lasting only a few nanoseconds. Before the experiment, they characterized the pristine diamond using confocal photoluminescence spectroscopy, ultraviolet-visible absorption spectroscopy, and Fourier-transform infrared spectroscopy to map existing defects, noting a low concentration of substitutional nitrogen compared to other diamond types.

After exposure, new optical emissions appeared near 563 and 579 nanometers in the laser-treated areas. These signals are associated with defect configurations related to carbon self-interstitials, which occur when carbon atoms occupy positions different from their normal lattice sites. Crucially, the pre-existing nitrogen-vacancy (NV) centers, which serve as quantum bits or qubits, remained largely unchanged. This demonstrates that the laser can modify one type of defect without disturbing another.

The new emissions did not increase indefinitely; instead, they peaked and then decreased under continued irradiation, suggesting complex defect transformations rather than simple creation. While the exact atomic mechanism remains an open question, the results indicate that nanosecond ultraviolet pulses can alter the optical defect structure of diamond while preserving quantum-relevant NV centers. This selective control could eventually allow scientists to deliberately design diamond’s defect landscape for specific applications in quantum technology.