Precision Infrared Spectroscopy Reaches Nanoscale

Associate Professor Ajanta Barh will develop a new laser-based technique that could make it possible to study the chemical properties of materials in volumes just a few molecules across. Backed by a Villum Experiment grant, the project could open new opportunities in biomedicine, electronics, thin-film technologies, and quantum science.

How does a material behave when you zoom in – way in…

At the nanoscale, materials can have properties that are very different from those observed in larger samples. But studying these tiny volumes with the same precision used in conventional spectroscopy has so far been extremely difficult.

Now, researchers at DTU are working to bring high-precision infrared spectroscopy down to the nanoscale.

Led by Ajanta Barh, the IR-nano project will develop a highly sensitive laser-based method for analysing materials in extremely small volumes – potentially down to just a few molecules.

Seeing materials at their smallest scale
Infrared spectroscopy is widely used to understand what materials are made of and how their molecules behave. By observing how a material interacts with infrared light, researchers can identify different molecules and learn about their chemical properties.

Conventional spectroscopy is limited by the fact that it typically examines relatively large quantities of material, containing millions of molecules.

“That can hide what’s happening at the smallest scale,” says Barh.

For materials used in technologies such as advanced electronics or quantum devices, however, it is often precisely these nanoscale properties that matter.

The IR-nano project will therefore develop a new approach that combines lasers with near-field measurements. Instead of analysing a large sample at once, the researchers aim to concentrate the measurement on an extremely small region of a material.

The ambition is to achieve orders-of-magnitude higher spectroscopic resolution than is currently possible at this scale.

From molecules to new technologies
Being able to identify and study molecules with high precision in nanoscale volumes could give researchers a much more detailed picture of how materials work, and why they sometimes behave differently when made very small.

So where is this usable? The method could be particularly valuable in fields where materials are already being engineered at the nanoscale.

In biomedicine, the technology could help researchers investigate tiny amounts of biological material, useful in drug discovery and interface analysis. In electronics and thin-film technologies, it could provide new ways of understanding and improving the materials used in increasingly small devices. And in quantum science, it could help reveal the purity of materials and devices important for controlling quantum systems.

If successful, IR-nano could give researchers a new way to explore matter at its smallest scales, turning the infrared spectrum into a tool for seeing not just what materials are made of, but how they behave when only a handful of molecules are involved.