Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 46: Laser Applications: Laser Spectroscopy

Q 46.1: Vortrag

Mittwoch, 25. März 2015, 14:30–14:45, K/HS2

Infrared spectroscopy near the diffraction limit with a high-brilliance mid-infrared femtosecond light source — •Frank Neubrech, Tobias Steinle, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Germany

We demonstrated highly sensitive infrared (IR) spectroscopy of sample volumes close to the diffraction limit by coupling a fiber-feedback optical parametric oscillator (OPO) to a conventional Fourier-Transform infrared (FTIR) spectrometer. The high brilliance and long-term stable infrared radiation with bandwidths up to 100 nm is easily tunable between 1.4 and 4.2 microns and thus enables low-noise infrared spectroscopy as we showed by measuring typical infrared vibrations in the range of 3 microns. Combined with surface-enhanced infrared spectroscopy (SEIRA), where the confined electromagnetic near-fields of resonantly excited metal nanoparticles are employed to enhance molecular vibrations, we realized the noise-free spectroscopic detection of a molecular monolayer of octadecanethiol. In comparison to conventional light sources and synchrotron radiation, our table-top OPO system features a significantly improved brilliance, making it highly suitable for analytical applications in life science and medical laboratories.