N. V. Morrow

Transition of laser cooling between standard and Raman optical lattices

Reduced-period optical lattices based on Raman transitions allow for sub-Doppler laser cooling. An important parameter of this Raman optical lattice is the frequency difference {delta}{sub d} between two virtual energy levels involved in the atom-field interaction scheme. In this work, we use experimental time-of-flight data and quantum simulations to characterize laser cooling in the Raman lattice as a function of {delta}{sub d}. Two different domains of laser cooling are identified. For small {delta}{sub d}, atoms are cooled due to a well-known mechanism that also occurs in standard optical lattices. For large {delta}{sub d}, atoms are cooled based on Raman transitions. We study the transition between the two domains of laser cooling in detail.

Atom Manipulation in Optical Lattices

Publisher Summary This chapter discusses applications of optical lattices on the field of wavepacket preparation and manipulation. In all experimental schemes presented, the lattices are used two-fold, namely, as an initialization tool to prepare suitable initial states of the quantum system, and as a platform on which the actual wavepacket experiments are performed. Therefore, the utilized lattices provide fast and robust laser-cooling of cold atoms into the lowest few quantum states of the lattice, and the decoherence rate of the trapped atoms caused by the fluorescence of the atoms in the lattice light is sufficiently low that coherent wave-packet motion can be observed over a number of periods of the motion. The chapter also discusses with two types of wave-packet motion. In one type, referred to as sloshing-type motion, wave-packets oscillate back and forth in individual lattice wells. The sloshing-type motion occurs within the spatial range of a single lattice well, with vanishing coupling between neighboring wells, on a length scale of a few tenths of the laser wavelength used to form the lattice. The second type of wave-packet motion discussed is periodic well-to-well tunneling. Tunneling measurements is used to investigate gauge potentials that were predicted by Dum and Olshanii. The chapter presents measurements on the influence of magnetic-field-induced level shifts on the tunneling behavior.

Effects of static and random magnetic fields on atoms in a gray optical lattice

We study magnetic field-induced modifications of the well-to-well tunneling behavior of atoms in a one-dimensional grey optical lattice. Measurements of the tunneling frequency as a function of the applied magnetic field reveal several tunneling resonances. We further show that the tunneling signal can be suppressed by randomly varying the symmetry of the potential wells. The tunneling is suppressed most effectively if the autocorrelation time of the lattice-well variation is on the order of the tunneling time. Experimental and theoretical results are in good agreement.

Raman optical lattice

We present a novel optical lattice of reduced periodicity that is based on Raman transitions. We demonstrate and characterize laser cooling in this lattice. Our observations are in agreement with theoretical results.

Effect of atomic density on wavepacket motion of atoms in an optical lattice

We investigate the dependence of oscillations of atoms trapped in an optical lattice on the atomic density. Our observations reflect a non-linear internal feedback mechanism.