  Inhomogeneous electric fields generated above two-dimensional electrode
structures have been used to transversely split beams of helium Rydberg atoms
into pairs of spatially separated components. The atomic beams had initial
longitudinal speeds of between 1700 and 2000 m/s and were prepared in Rydberg
states with principle quantum number $n=52$ and electric dipole moments of up
to 8700 D by resonance-enhanced two-color two-photon laser excitation from the
metastable 1s2s $^3$S$_1$ level. Upon exiting the beam splitter the ensembles
of Rydberg atoms were separated by up to 15.6 mm and were detected by pulsed
electric field ionization. Effects of amplitude modulation of the electric
fields of the beam splitter were shown to cause particle losses through
transitions into unconfined Rydberg-Stark states.
