Femtosecond laser system

• Subject Area: Physical Chemistry
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 517517887

Over the last three decades, non-linear Raman microscopy techniques based on coherent anti-Stokes Raman scattering or stimulated Raman scattering have become attractive tools for the investigation of biological and material scientific samples. Compared to fluorescence techniques, the main drawback of both methods is their lack in sensitivity. Main aim of this proposal is the implementation of a setup for coherent anti-Stokes Raman scattering microscopy and stimulated Raman scattering microscopy with sensitivities comparable to that of confocal fluorescence microscopy and its application in various different experiments. To this end, electronic pre-resonance enhancement of the non-linear Raman signals shall be exploited. This requires the use of chromophores with suitable electronic absorptions. While the principle of the planned experiment has recently been demonstrated by us and another group, experiments performed so far used excitation lasers working in the near-infrared spectral region. This limits the applicability of the proposed approach to very small range of molecules. An important part of our main aim therefore is to shift the excitation wavelength further into the visible spectral region. This would give access to a huge range of well characterized chromophores. Once built, the experimental setup shall mainly be employed to investigate various types of samples from biology and material sample. Apart from this, we also want to use the setup to further push the sensitivity limits to detecting vibrational spectra of single molecules.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Femtosekundenlasersystem für nicht-lineare Raman-Mikroskopie
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Universität Konstanz
• Leader: Professor Dr. Andreas Zumbusch