Scientists from the Department of Physical Chemistry at the Fritz Haber Institute of the Max Planck Society have made a significant discovery in the field of nanotechnology, as shown in their recent publication in Advanced materialsTheir article entitled “Spectroscopic and Interferometric Sum-Frequency Imaging of Strongly Coupled Phonon Polaritons in SiC Metasurfaces” presents a novel microscopy method that enables unprecedented visualization of nanostructures and their optical properties.

Metamaterials engineered at the nanoscale exhibit unique properties not found in naturally occurring materials. These properties arise from their nanoscale building blocks, which have previously been difficult to observe directly due to their size, which is smaller than the wavelength of light. The team’s research overcomes this limitation by using a new microscopy technique that can visualize both the nano and macro structures of these materials simultaneously.

The most important result of this research is a methodological breakthrough that enables the visualization of structures that were previously too small to be seen with conventional microscopy. Through the innovative use of light, the scientists have figured out how to “trap” one color of light in the structure and, by mixing it with a second color that can leave the structure, visualize this trapped light. This trick reveals the hidden world of optical metamaterials at the nanoscale.

This achievement is the result of more than five years of dedicated research and development exploiting the unique properties of the free-electron laser (FEL) at the Fritz Haber Institute. This type of microscopy is particularly special because it enables a deeper understanding of metasurfaces and paves the way for advances in technologies such as lens design, with the ultimate goal of developing flatter, more efficient optical devices.

By better understanding metasurfaces, this research opens the door to the development of novel light sources and the design of coherent thermal light sources.

“We’re only at the beginning,” the research team explains, “but the impact of our work on the field of flat optics and beyond is enormous. Our technique allows us not only to see the full performance of these nanostructures, but also to improve them by shrinking 3D optics down to 2D, making everything smaller and flatter.”