Stark deceleration and trapping of hydrogen Rydberg molecules

Full text: Recent progress in the development of methods to decelerate and manipulate the translational motion of Rydberg atoms and molecules in the gas phase using inhomogeneous electric fields has led to the experimental realization of Rydberg atom optics elements including a lens, a mirror and two- and three-dimensional traps. These experiments make use of the very large electric dipole moment of Rydberg Stark states and have demonstrated the possibility to stop a pulsed supersonic beam of seeded atomic hydrogen traveling with an initial velocity of 700 ms-1 within a distance of 2 - 3 mm and within ∼ 5 μs using electric fields with a strength of a few kV cm-1. We have extended these methods to control the translational motion of molecules and present the results of recent experiments in which we have decelerated and loaded hydrogen Rydberg molecules into a three-dimensional electrostatic trap. The experiments use a multiphoton excitation sequence to excite nonpenetrating (l ≥ 3) Rydberg-Stark states with principal quantum number in the range n = 20-35 using circularly polarized laser radiation. These states are long-lived and the avoided crossings between Stark states are reduced to the extent that they are traversed diabatically during deceleration. We discuss the method employed to decelerate and load the Rydberg molecules into the trap along with trap loss mechanisms including predissociation, fluorescence and collisional processes. (author)