  Experiments and numerical simulations are described that develop quantitative
understanding of atomic motion near the surfaces of nanoscopic photonic crystal
waveguides (PCWs). Ultracold atoms are delivered from a moving optical lattice
into the PCW. Synchronous with the moving lattice, transmission spectra for a
guided-mode probe field are recorded as functions of lattice transport time and
frequency detuning of the probe beam. By way of measurements such as these, we
have been able to validate quantitatively our numerical simulations, which are
based upon detailed understanding of atomic trajectories that pass around and
through nanoscopic regions of the PCW under the influence of optical and
surface forces. The resolution for mapping atomic motion is roughly 50 nm in
space and 100 ns in time. By introducing auxiliary guided mode (GM) fields that
provide spatially varying AC-Stark shifts, we have, to some degree, begun to
control atomic trajectories, such as to enhance the flux into to the central
vacuum gap of the PCW at predetermined times and with known AC-Stark shifts.
Applications of these capabilities include enabling high fractional filling of
optical trap sites within PCWs, calibration of optical fields within PCWs, and
utilization of the time-dependent, optically dense atomic medium for novel
nonlinear optical experiments.
