Quantum cascade laser for nano-FTIR spectroscopy

• Subject Area: Fluid Mechanics, Technical Thermodynamics and Thermal Energy Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 578077116

The proposal involves replacing a tunable broadband laser, which has been used for s-SNOM and AFM-IR measurements to date, with a multichip quantum cascade laser (QCL) system. The existing broadband laser can no longer be used efficiently due to the manufacturer's imminent discontinuation of maintenance services and the device's age-related susceptibility to malfunction. Since the nano-FTIR activities of the participating working groups are focused on AFM-IR measurements on macromolecular samples and are to be continued accordingly, a hyperspectral QCL was chosen. Although this QCL is not suitable for scattering-type Scanning Near-field Optical Microscopy (s-SNOM) use, it provides much higher sensitivity in AFM-IR mode than the previously used broadband laser. This makes this laser model particularly well suited for analyzing organic and polymer sample surfaces (e.g., polymers, self-assembled monolayers). The working groups involved at the University of Paderborn use AFM-IR measurements to analyze the surface and interface chemistry of heterogeneous organic and macromolecular systems. Relevant topics include smart polymers, materials for energy conversion, polymer coatings, adhesives, implant materials, and bionanomaterials. By combining complementary microscopic, spectroscopic, and electrochemical measurement techniques available in the participating working groups, the AFM-IR method allows the correlation of local material compositions with the functional properties of materials and coatings. Due to the higher sensitivity of AFM-IR measurement based on the proposed laser, in combination with the surface-sensitive mode of AFM-IR, it is now also possible to measure very thin coatings on polymer and metal substrates and nanoscopic particles in polymer matrices.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Quantenkaskadenlaser für die Nano-FTIR-Spektroskopie (Erneuerung)
• Instrumentation Group: 5730 Spezielle Laser und -Stabilisierungsgeräte (Frequenz, Mode)
• Applicant Institution: Universität Paderborn
• Leader: Professor Dr.-Ing. Guido Grundmeier