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MO: Fachverband Molekülphysik

MO 8: Kalte Moleküle I (gemeinsam mit Q)

MO 8.1: Hauptvortrag

Dienstag, 11. März 2008, 08:30–09:00, 3G

Cold Polar Molecules: From Production to State-Selective Detection — •Pepijn W.H. Pinkse, Laurens D. van Buuren, Michael Motsch, Markus Schenk, Christian Sommer, Martin Zeppenfeld, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching

Cold polar molecules promise opportunities in various research fields such as chemistry, metrology, molecular physics and quantum information processing. To this end, advanced production, trapping and cooling techniques are required.

An overview will be given of the methods developed in our laboratory: we filter slow molecules out of a thermal ensemble by exploiting the Stark effect in polar molecules such as formaldehyde, ammonia and water. The thermal ensemble in the source can be at room temperature or at cryogenic temperature, in which case helium is used as a cold buffer gas. Using suitably shaped electric fields, slow polar molecules are guided into ultrahigh vacuum, where we can store them in an electric trap.

While the motional energy of the filtered molecules is in the 1K range, the rotational temperature is higher. Depending on the temperature of the source and the molecular constants, many rotational states can be occupied. As a preparation for optical measurements, we performed high-resolution molecular UV spectroscopy on formaldehyde. With the gained information, we can now measure the distribution over the internal states of guided formaldehyde by state-selectively depleting the beam by optical pumping. Precise knowledge over the state distribution will be vital for further cooling down the molecules, for instance by means of an optical cavity.