Cold Collisions in a Molecular Synchrotron

Ubachs, W.M.G. [Promotor]Bethlem, H.L. [Copromotor

Molecular Fountain

The resolution of any spectroscopic or interferometric experiment is ultimately limited by the total time a particle is interrogated. We here demonstrate the first molecular fountain, a development which permits hitherto unattainably long interrogation times with molecules. In our experiments, ammonia molecules are decelerated and cooled using electric fields, launched upwards with a velocity between 1.4 and 1.9\,m/s and observed as they fall back under gravity. A combination of quadrupole lenses and bunching elements is used to shape the beam such that it has a large position spread and a small velocity spread (corresponding to a transverse temperature of $<$10\,$\mu$K and a longitudinal temperature of $<$1\,$\mu$K) when the molecules are in free fall, while being strongly focused at the detection region. The molecules are in free fall for up to 266\,milliseconds, making it possible to perform sub-Hz measurements in molecular systems and paving the way for stringent tests of fundamental physics theories

Investigating cooling and deceleration of SrF molecules

De begeleider en/of auteur heeft geen toestemming gegeven tot het openbaar maken van de scriptie. The supervisor and/or the author did not authorize public publication of the thesis.

Femtosecond laser detection of Stark-decelerated and trapped methylfluoride molecules

We demonstrate deceleration and trapping of methylfluoride (CH3F) molecules in the low-field-seeking component of the J=1,K=1 state using a combination of a conventional Stark decelerator and a traveling wave decelerator. The methylfluoride molecules are detected by nonresonant multiphoton ionization using a femtosecond laser. Subsequent mass and velocity selection of the produced ions enables us to eliminate most background signal resulting from thermal gas in our vacuum chamber. This detection method can be applied to virtually any molecule, thereby enhancing the scope of molecules that can be Stark decelerated. Methylfluoride is so far the heaviest and most complex molecule that has been decelerated to rest. Typically we trap 2×104 CH3F molecules at a peak density of 4.5×107 cm-3 and a temperature of 40 mK