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.