Mitigation of loss within a molecular Stark decelerator

Mitigation of loss within a molecular Stark deceleratorRecent development of cold polar-molecule sources promises to reveal many interesting, and hitherto unex¬plored, molecular interaction dynamics. The permanent electric dipole moment possessed by polar molecules pro¬vides a new type of interaction in the ultracold environ¬ment. This electric dipole-dipole interaction (and control over it) should give rise to unique physics and chemistry including novel cold-collision dynamics [1,2] and quantum information processing [3].
To date, cold polar-molecule samples have been produced most successfully via three different mecha¬nisms: buffer gas cooling [4,12]; photo- and magneto- association [5-8]; and Stark deceleration [9]. Buffer gas cooling achieves temperatures below 1 K through ther- malization of molecules with a He buffer. This technique produces relatively large densities (108 cm—3) of polar ground-state molecules. However, cooling below ~100 mK has not yet been achieved because the He buffer gas has not been removed quickly enough for evaporative cool¬ing [12]. Photoassociation achieves the lowest molecular temperatures of these techniques 卜 100 /xK), but is lim¬ited to molecules whose atomic constituents are amenable to laser-cooling. Furthermore, molecules in their ground
a e-mail: sawyerbc@colorado.edu
b Present address: Department of Physics, University of Illinois, Urbana, IL 61801-3080, USA vibrational state are not readily produced, yielding species with relatively small effective electric dipoles, although this problem can be overcome with more sophisticated laser control techniques [6,14]. Stark deceleration exists as an