Quantum sensing promises measurement capabilities that far exceed classical technologies. Using quantum properties of matter, quantum sensors can detect extremely small magnetic, electrical and thermal signals, creating new opportunities across materials science, energy systems, health, advanced manufacturing, and the study of molecular and non‑equilibrium biological systems.
Quantum sensors are so sensitive that interference from their own surfaces overwhelms the signals they are designed to measure. Until this problem is solved, quantum sensing remains fragile, difficult to scale, and largely confined to controlled laboratory experiments.
In work published in ACS Nano, QUBIC Chief Investigator Associate Professor David Simpson and collaborators directly addressed this challenge by engineering the surface of fluorescent nanodiamonds, which are a leading solid‑state quantum sensing platform.
Nanodiamonds containing nitrogen‑vacancy (NV) centres can operate at room temperature and offer nanometre‑scale spatial resolution. However, when these quantum defects are positioned close to the nanodiamond surface – a requirement for high‑resolution sensing – surface‑induced noise rapidly degrades performance. This surface noise has been a persistent barrier to practical quantum sensing.
By deliberately modifying nanodiamond surface chemistry and applying ultra‑thin, uniform silica coatings, the researchers suppressed surface‑generated noise and extended spin relaxation times into the millisecond regime, significantly improving the stability and performance of nanodiamond quantum sensors.
Crucially, this work demonstrates that stabilising quantum sensor performance can be achieved through materials engineering, without reliance on complex quantum control techniques. By clearly linking surface chemistry to quantum behaviour, Associate Professor Simpson and his team transformed surface modification from trial and error into a method that can be deliberately designed and optimised.
This capability is essential for quantum sensing in complex, dynamic environments that demand extreme spatial resolution, such as observing how new materials behave at the nanoscale, monitoring chemical reactions as they happen, improving energy technologies like batteries, and studying molecular‑scale processes as they unfold.
For QUBIC, this research strengthens Centre objectives by delivering a robust, scalable quantum sensing platform that underpins translation across biotechnology, including agriculture, biosecurity, clean energy, and health.
Read the paper here: Functionalized Fluorescent Nanodiamonds with Millisecond Spin Relaxation Times
