In a groundbreaking achievement, researchers at the University of Cambridge have unveiled a quantum sensor made from hexagonal boron nitride (hBN). This innovative sensor promises to revolutionize magnetic field detection at the nanoscale, opening doors to unprecedented imaging capabilities. The discovery, published in Nature Communications, marks a significant leap forward in quantum technology.
The hBN-based sensor can detect magnetic fields at the nanoscale in multiple directions, offering a broader dynamic range than previous diamond-based sensors. "Quantum sensors allow us to detect nanoscale variations of various quantities," explained Dr. Carmem Gilardoni, co-first author of the study. "This work takes that capability to the next level using hBN, a material that's not only compatible with nanoscale applications but also offers new degrees of freedom."
Unlike diamond-based sensors, which have limitations in detecting magnetic fields along a single axis, the hBN sensor overcomes these challenges. The researchers found that the sensor's wide dynamic range and ability to detect vectorial magnetic fields stem from the low symmetry of the hBN defects and their favorable excited-state optical properties. This advancement could lead to a deeper understanding of magnetic phenomena and nanomaterials.
hBN, a two-dimensional material similar to graphene, is ideal for quantum sensing applications. Its atomic-scale defects absorb and emit visible light, making it sensitive to local magnetic conditions. The team used optically detected magnetic resonance (ODMR) to study the sensor's response to magnetic fields. This technique allows for imaging magnetic phenomena and nanomaterials in ways previously impossible.
"This sensor could open the door to studying magnetic phenomena in new material systems, or with higher spatial resolution than has been done before,” said Prof. Hannah Stern, who co-led the research. The atomically-thin nature of hBN also opens exciting possibilities for atomic-scale spatial mapping of magnetic fields, paving the way for groundbreaking discoveries in various fields.