Gerd Klose

Resolved-Sideband Raman Cooling to the Ground State of an Optical Lattice

We trap neutral Cs atoms in a two-dimensional optical lattice and cool them close to the zero point of motion by resolved-sideband Raman cooling. Sideband cooling occurs via transitions between the vibrational manifolds associated with a pair of magnetic sublevels, and the required Raman coupling is provided by the lattice potential itself. We obtain mean vibrational excitations

Measuring the Quantum State of a Large Angular Momentum

{\overline{n}}_{x}\ensuremath{\approx}{\overline{n}}_{y}l0.024

External mode locking with feedback from a self‐pumped phase‐conjugator BaTiO3 crystal

, corresponding to a population

Atom trapping in deeply bound states of a far-off-resonance optical lattice

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Quantum control and information processing in optical lattices

in the vibrational ground state. Atoms in the ground state of an optical lattice provide a new system in which to explore quantum state control and subrecoil laser cooling.

Enhanced laser cooling and state preparation in an optical lattice with a magnetic field

We demonstrate a general method to measure the quantum state of an angular momentum of arbitrary magnitude. The (2F+1)x(2F+1) density matrix is completely determined from a set of Stern-Gerlach measurements with (4F+1) different orientations of the quantization axis. We implement the protocol for laser cooled Cesium atoms in the 6S(1/2)(F = 4) hyperfine ground state and apply it to a variety of test states prepared by optical pumping and Larmor precession. A comparison of input and measured states shows typical reconstruction fidelities F >/~0.95.

QUANTUM CONTROL AND INFORMATION PROCESSING

An external mode locking technique using RF modulation by an acousto-optic modulator and feedback from a phase-conjugate mirror is presented. A photorefractive BaTiO3 crystal is arranged in self- pumped phase-conjugator geometry. The setup is completely self- aligning and subnanosecond pulses are easily observed for He-Ne (632.8 nm), Ar 1 (514.5 nm), and He-Cd (442 nm) lasers.