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MO: Fachverband Molekülphysik
MO 21: Advanced Time-Resolved Spectroscopy
MO 21.7: Vortrag
Donnerstag, 8. März 2018, 15:30–15:45, PA 2.150
Shaper based infrared spectroscopy in a nonlinear Raman setup — •Niklas Müller, Lukas Brückner, and Marcus Motzkus — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg
The infrared and Raman sensitivities differ for a vibrational transition, particularly in molecules with inversion symmetry. Therefore a combination of both methods yields to more information about the molecules. Combining the established coherent anti-Stokes Raman scattering (CARS) setup [1] with a tunable narrowband infrared light source, we are able to do both CARS and infrared spectroscopy in a single-beam setup. Broadband laser pulses spectrally centered at 800 nm are shaped by a liquid crystal spatial light modulator to generate either background-free coherent anti-Stokes signal in a sample or narrowband tunable infrared light in a birefringent crystal beforehand. The infrared light is generated by difference-frequency generation in a thin LiIO3 crystal by phase and polarization shaped laser pulses. On the one hand, the large tunability (>1500 cm−1) is based on the broad phase matching condition of the thin crystal. On the other hand, the narrowband behavior (<25 cm−1) is achieved by chirped laser pulses yielding to the same instantaneous frequency difference in the crystal.
[1] L. Brückner, et al. JOSA B 33 1482 (2016)