We adapt our measuring systems individually to the needs of our customers. This includes both the application and the evaluation software, which presents the important target variables in a clear and user-friendly manner.
Optical Coherence Tomography (OCT)
Functional properties require a minimum thickness because unnecessarily thick layers waste resources and increase manufacturing costs. There is now a solution for measuring very thin, semitransparent layers: Optical Coherence Tomography (OCT). This method was originally developed for the depth-resolved visualization of biological and medical materials.
Thanks to intensive research, it has now also established itself outside medicine. High-resolution sample cross-sections – which are generated in real time with visible light or infrared light and completely non-destructively – make OCT the ideal non-contact inspection technology for many applications.
Classical Spectroscopy and Hyperspectral Imaging
In spectroscopy it is primarily investigated how the sample to be examined changes the spectrum of the incident light. Based on these changes, we draw conclusions about the substance under test and can even identify them in the best case. The term »light« is a synonym for any part of the electromagnetic spectrum, from UV to visual to infrared (Near-infrared (NIR), Short Wavelength Infrared (SWIR), Long Wavelength Infrared (LWIR)) and Terahertz.
The observed spectrum changes can be caused by absorption, emission, fluorescence and the Raman effect. Transmission, reflection and ATR can be used as measurement arrangements. While in »classical« spectroscopy samples are examined selectively, in hyperspectral imaging sample images with at least 100 spectral channels are recorded. Automated, chemometric evaluation methods support the interpretation of the spectra.
In recent decades, great progress has been made in the targeted generation, manipulation, and detection of quantum states of light. Optical experiments have played a leading role in this regard, demonstrating phenomena such as quantum entanglement and making them useful for practical applications, ultimately leading to a new division of quantum technologies. In addition to the well-known fields of quantum computing and quantum communication, sensing with photonic quantum states plays a special role in these technologies, as it is similar to established methods of classical light sensing, such as spectroscopy and microscopy, and also has technological overlaps.
In the context of this so-called »second quantum revolution«, the targeted generation of photonic quantum states, such as entangled photons, has proven to be particularly useful. By using strongly correlated photon pairs in different wavelength divisions, information can be »transferred« between these divisions in nonlinear interferometers, thus spectrally separating the interaction with the studied object and the registration of the information.
The Fraunhofer lead project »QUILT« aimed to implement this concept in different wavelength ranges and to make new measurement techniques for imaging, spectroscopy and metrology applicable in practical applications. The most extreme wavelength spread to date was achieved by generating photon pairs in which one partner was in the visible and the other in the terahertz range. Using this measurement principle, it has already been possible to successfully transfer and detect layer thickness and spectroscopic information collected in the NIR or terahertz division into the visible range.
In doing so, this work represents significant scientific and technical contributions to the fields of metrology, spectroscopy, and tomography and shapes the current state of research in these divisions. At the same time, quantum optical methods also open up new possibilities for the further development of classical measurement techniques. In this context, quantum states are replaced by classically generated states, which can be generated much more effectively. This conversion makes it possible to perform measurements much faster and more efficiently. In addition, the development of simulations for the generation of photon pairs and for the design of nonlinear interferometers played a central role in this research.