Diamonds are not only prized for their beauty—they also hold secrets that could transform future quantum technologies.
Researchers at The City College of New York have discovered an unexpected property of tiny defects inside diamonds, known as nitrogen-vacancy (NV) centers, that could open new doors in quantum information science.
Their findings were recently published in Nature Nanotechnology.
NV centers are special spots in the diamond crystal where a nitrogen atom replaces a carbon atom and a nearby gap is left in the lattice.
These defects can trap electrons, which in turn can interact with light in ways that make NV centers useful as “quantum emitters.”
For years, scientists have been excited about NV centers because they can store quantum information and emit photons that carry that information.
However, one problem has always stood in the way: the light they produce comes out in a broad, messy spectrum that is difficult to control.
What was once seen as a drawback has now turned into a surprising advantage.
The team, led by physics professor Carlos A. Meriles, discovered that this broad emission actually enables a new type of coupling when the NV center is brought close to a specially designed photonic structure.
By moving the diamond defect around with a scanning tip, the researchers found that the emitted light reshaped itself in unusual ways, revealing interactions that had never been observed before.
This discovery has big implications for quantum technology.
One of the biggest challenges in building quantum computers and communication devices is maintaining stable links between quantum bits, or qubits. NV centers in diamonds are promising candidates, but issues like spectral diffusion—random shifts in the emitted light—have slowed progress.
The newly observed coupling could help overcome this barrier, creating stronger, more reliable connections between qubits through spin–photon and spin–spin entanglement directly on a chip.
Beyond quantum computing, the research also uncovered a surprising sensing capability. By studying how the NV emission changed in the presence of the photonic structure, the team was able to create detailed images of the waveguide’s photonic modes, including information about the polarization of the light.
This ability to map light patterns with such high precision could be extended beyond photonics.
For example, Meriles suggests the same approach might one day be used to detect chiral molecules—molecules that come in left- and right-handed versions and play a central role in biology and medicine.
The researchers plan to continue exploring both avenues: probing the fundamental physics of how quantum emitters interact with engineered structures and developing practical sensing tools inspired by the same principles.
With diamonds leading the way, the study shows how even well-studied materials can still surprise us and open up new frontiers in technology.
