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CDL

Christian Doppler Laboratory

Georg Ramer

Motivation

Within the Christian Doppler Laboratory for Advanced Mid-Infrared Laser Spectroscopy in (Bio-)process Analytics, together with our industrial partners DRS Daylight Solutions, Takeda, Eralytics and attocube, we develop novel chemical analysis techniques using external cavity quantum cascade lasers. 

Areas of Research

  • 1

    1Vibrational circular dichroism (VCD) is one of few techniques hat can detect enatiomers and provide information on enantiomeric excess. Unfortunately, measurement times of this technique are notoriously long. Using quantum cascade lasers we improve the throughput of the technique to the point where it can be used for process analytics. 

  • 2

    2We use the fact that  Kramers-Kronig transform is a linear map between the imaginary and the real part of the refractive index for high-dynamic range mid-IR spectroscopy.  

  • 3

    3We employ photothermal spectroscopy for highly sensitive chemical trace detection in liquids. Supported by digital twinning approach to quickly develop and iterate sensor designs. 

  • 4

    4Using machine learning and physics supported modelling we develop novel approaches for accurate quantitation in complex media.

  • 5

    5Using new sampling schemes we are developing single protein specific secondary structure analysis techniques. 

  • 6

    6Nanoscale chemical analysis using AFM-IR is a 2D imaging technique with nanometer spatial resolution. We will turn it into a 3D technique using nanoscale tomography. 

Researchers

Georg Ramer, Alicja Dabrowska, Michael Luxner, Lena Neubauer, Lisa Riedlsperger, Verena Rohringer

Publications

Zhang, Y.; Sam, S.; Mendoza-Castro, J. H.; Lendl, B.; Ramer, G.; O’Faolain, L. Waveguide Bragg Grating-Enhanced Microcantilever-Based Force Sensor. Photonics and Nanostructures – Fundamentals and Applications 2026, 70, 101522. https://doi.org/10.1016/j.photonics.2026.101522.

Cheng, H.; Lukasievicz, G. V. B.; Dabrowska, A.; Astrath, N. G. C.; Ramer, G.; Lendl, B. Mid-IR Photothermal Lens Sensing for Trace Water Detection in Organic Solvents. Measurement 2026, 259, 119581. https://doi.org/10.1016/j.measurement.2025.119581.

Zhang, Y.; Yilmaz, U.; Vorobev, A. S.; Iadanza, S.; O’Faolain, L.; Lendl, B.; Ramer, G. Experimental and Theoretical Insights into Nanoscale AFM-IR Imaging of Complex Heterogeneous Structures. Anal. Chem. 2025, 97 (38), 21141–21149. https://doi.org/10.1021/acs.analchem.5c04707.

Zhang, Y.; Vorobev, A. S.; Sam, S.; Badri, S. H.; David, M.; Lendl, B.; Ramer, G.; O’Faolain, L. Single-Mode Ring Resonator-Based Optomechanical Transducers for Advanced Atomic Force Sensing. ACS Photonics 2025. https://doi.org/10.1021/acsphotonics.5c01914.

Yilmaz, U.; Lukasievicz, G. V. B.; Sehn, E.; Zhang, Y.; Astrath, N. G. C.; Ramer, G.; Lendl, B. Novel Insights into Nanoscale Surface Displacement Detection in Polystyrene Thin Films Using Photothermal Mirror- and Atomic Force Microscopy-Mid-IR Spectroscopy. RSC Adv. 2025, 15 (12), 9243–9253. https://doi.org/10.1039/D5RA00555H.

Vijayakumar, S.; Schwaighofer, A.; de Juan, A.; Rocha de Oliveira, R.; Mach-Aigner, A.; Lendl, B.; Ramer, G. Fusion of Incomplete QCL-IR and ECD Datasets Using MCR-ALS to Extend the Viable Concentration Range for Studying Protein Denaturation. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2026, 349, 127340. https://doi.org/10.1016/j.saa.2025.127340.

Holub, E.; Hondl, N.; Wöhrer, S.; Lendl, B.; Ramer, G. Not Just Better Resolution: A Detailed Study of the Signal Distribution in Mid-Infrared Optical Photothermal Imaging. Anal. Chem. 2025, 97 (39), 21418–21427. https://doi.org/10.1021/acs.analchem.5c03194.

Zhang, Y.; Astrath, N. G. C.; Lukasievicz, G. V. B.; Vorobev, A. S.; O’Faolain, L.; Ramer, G.; Lendl, B. Understanding and Designing Photothermal Responses in Complex Layered Systems. Sci Rep 2025, 15 (1), 26173. https://doi.org/10.1038/s41598-025-11585-8.

Zhang, Y.; Astrath, N. G. C.; Neubauer, L.; Ramer, G.; Lendl, B. Revealing Buried Thermal Responses in Polymer Multilayers Using Photothermal Mirror Infrared Spectroscopy.

Hondl, N.; Neubauer, L.; Ramos-Garcia, V.; Kuligowski, J.; Bishara, M.; Sevcsik, E.; Lendl, B.; Ramer, G. Method for Mid-IR Spectroscopy of Extracellular Vesicles at the Subvesicle Level. ACS Meas. Sci. Au 2025. https://doi.org/10.1021/acsmeasuresciau.5c00001.

Zhang, Y.; Yilmaz, U.; Lukasievicz, G. V. B.; O’Faolain, L.; Lendl, B.; Ramer, G. An Analytical Model of Label-Free Nanoscale Chemical Imaging Reveals Avenues toward Improved Spatial Resolution and Sensitivity. Proc. Natl. Acad. Sci. 2025, 122 (4), e2403079122. https://doi.org/10.1073/pnas.2403079122.

Hermann, D.-R.; Ramer, G.; Lendl, B. External Cavity Quantum Cascade Laser Vibrational Circular Dichroism Spectroscopy for Fast and Sensitive Analysis of Proteins at Low Concentrations. Anal. Chem. 2024, 96 (49), 19363–19369. https://doi.org/10.1021/acs.analchem.4c03498.