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MO: Fachverband Molekülphysik
MO 8: Cold Molecules
MO 8.5: Vortrag
Freitag, 24. September 2021, 11:45–12:00, H1
Buffer gas cooling and optical cycling of AlF molecules — •Simon Hofsäss1, Maximilian Doppelbauer1, Sid Wright1, Sebastian Kray1, Boris Sartakov2, Jesús Pérez-Ríos1, Gerard Meijer1, and Stefan Truppe1 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia
Aluminium monofluoride (AlF) is a promising candidate for a high-density magneto-optical trap (MOT) of molecules. Here, we show that AlF can be produced efficiently in a bright, pulsed cryogenic buffer gas beam, and demonstrate rapid optical cycling on the Q rotational lines of the A1Π ↔ X1Σ+ transition at 228nm. We measure the brightness of the molecular beam to be >1012 molecules per steradian per pulse in a single rotational state and present a new method to determine its velocity distribution accurately in a single molecular pulse. The photon scattering rate is measured using three different methods and compared to theoretical predictions of the optical Bloch equations and a rate equation model. An exceptionally high scattering rate of up to 42(7) x 106 s−1 can be sustained despite the large number of Zeeman sublevels (up to 216 for the Q(4) transition) involved in the optical cycle. We demonstrate that losses from the optical cycle due to vibrational branching to X1Σ+, v=1 can be addressed efficiently with a repump laser, allowing us to scatter about 104 photons using two lasers. Further, we investigate two other loss channels, photo-ionisation and parity mixing by stray electric fields. The upper bounds for these effects are sufficiently low to allow loading the molecules into a MOT.