A team of researchers from Paderborn is improving optical coherence tomography (OCT), a widely used measurement technique in medicine and Materials Science. They have combined classic OCT with quantum effects - entirely in integrated optical waveguides - paving the way for smaller and more efficient devices.
Optical coherence tomography with undetected photons is a promising technique for studying layered materials at wavelengths such as the mid-infrared, where conventional methods face challenges.
However, its wide application has so far been limited by its reliance on large, bulky optical setups that require high laser power and are difficult to miniaturise.
In this work, we have developed a more compact system based on integrated waveguides that opens a path to smaller and more practical devices.
We found that a less commonly used measurement approach - so-called induced coherence - works particularly well in this integrated setup.
This result not only improves performance, but also provides valuable information for the development of future compact quantum sensor systems.
The results bring us one step closer to real-world applications of integrated quantum spectroscopy.
This project has received funding from the German Federal Ministry of Research, Technology and Space (BMFTR) under grant agreement No 13N16352 (E2TPA) and from the European Union's Horizon Europe research and innovation programme under grant agreement No 101070700 (MIRAQLS).