Erlangen 2018 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 13: Laser Development and Applications (joint session Q/A)
Q 13.5: Vortrag
Montag, 5. März 2018, 15:00–15:15, K 0.023
Monitoring protein configurations in the fingerprint region with micro-FTIR spectroscopy using a 98 fs solid-state laser tunable from 1.33 to 8 µm at 73 MHz repetition rate — •Florian Mörz1, Rostyslav Semenyshyn1, Frank Neubrech2, Tobias Steinle3, Andy Steinmann1, and Harald Giessen1 — 14. Physikalisches Institut, Universität Stuttgart — 2Kirchhoff-Institut für Physik, Universität Heidelberg — 3ICFO-Institut de Ciencies Fotoniques, Barcelona, Spanien
Configurations of poly-L-lysine proteins using vibrational resonances at 6 µm (1667 cm-1) are monitored by employing a broadband femtosecond laser for micro-FTIR spectroscopy in combination with resonant surface-enhanced infrared absorption (SEIRA) spectroscopy, using a single gold nanoantenna. Our tabletop laser system exceeds the sensitivity of standard FTIR light sources due to an orders of magnitude higher brilliance. Absorption signals as small as 0.5% are detected without averaging, compared to 6.4% using a globar, at 10x10 µm2 spatial resolution. By pumping a fiber-feedback optical parametric oscillator and a post-amplifier, signal and idler beams spanning from 1.33-2.0 and 2.1-4.6 µm are generated. The tuning range is extended to 8 µm by difference frequency generation between the signal and idler beams. At 7 µm a wavelength stability with fluctuations smaller than 0.1% rms over 9 hours is observed, without applying electronic stabilization. Thus our design is distinctly superior over other systems based on free-space OPOs and applications such as protein sensing using FTIR spectroscopy in combination with SEIRA are enabled.