Rostock 2019 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 10: Posters 1: Cold Molecules, High Resolution Spectroscopy, and Theory
MO 10.3: Poster
Dienstag, 12. März 2019, 16:30–18:30, S Foyer LLM
State selective laser induced fluorescence detection of cold formaldehyde — •Maximilian Löw, Martin Ibrügger, Alexander Prehn, Martin Zeppenfeld, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching
Because of their rich internal structure and long-range dipole-dipole interactions, cold polar molecules have great potential for a wide variety of different applications. In our experiment, we are able to cool formaldehyde (H2CO) down to sub-millikelvin temperatures by applying optoelectrical Sisyphus cooling [1]. In the past, the molecules were detected in a robust and reliable way using a quadrupole mass spectrometer. However, the low detection efficiency of ∼10−4 led to long measurement times thereby severly limiting the experiment.
Here, we present a new detection setup based on laser-induced fluorescence (LIF) of formaldehyde. A quantum yield of up to 30% for radiative decay from the excited state and light collection optics covering a solid angle of ∼70% lead to an increase in detection efficiency of up to a factor of 30. A high signal to noise ratio was achieved by reducing background light by many orders of magnitude. Additionally, we can now detect molecules state selectively, including discrimination of different rotational M-sublevels. This makes LIF detection a powerful tool which will enable us to substantially improve our understanding of our experiment and promises exciting future prospects.
[1] A. Prehn et al., Phys. Rev. Lett. 116, 063005 (2016).