Southwest Quantum Information and Technology

Observation of stochastic resonance and unidirectional atomic propagation in optical lattices

Presenting Author: Casey Scoggins, Miami University
Contributing Author(s): Daniel Wingert, Jordan Churi, Angela Noreck, Grant Brown, Kefeng Jiang, Alexander Staron, Samir Bali

By illuminating a 3D dissipative optical lattice with a weak frequency-scanning probe beam and detecting the probe transmission spectrum we observe a resonant enhancement in the directed propagation of cold atoms as we vary the rate of random photon scattering. The directed propagation is induced by probe intensities less than 1% of the total lattice intensity, and occurs perpendicular to probe propagation along a particular symmetry axis of the lattice in the + / - directions. We experimentally characterize this stochastic resonance as a function of probe intensity and lattice well-depth. We show that by varying the angle of incidence of the probe beam on the lattice we can alter the nature of directed propagation - from bidirectional to unidirectional. A simple one-dimensional model reveals how the probe-modified ground state potentials and optical pumping rates conspire to create directed atomic propagation within a randomly diffusing sample. We discuss the possibility for further analysis of the directed motion in the lattice, in terms of the dwell-time in a particular well versus the time taken to hop between adjacent wells, by direct measurement of polarization-sensitive photon statistics of the scattered light. We gratefully acknowledge funding by the Army Research Office.

(Session 5 : Thursday from 12:00pm-2:00 pm)