Pimonpan Sompet

Preparation of a single atom in an optical microtrap

We investigate the use of light assisted collisions for the deterministic preparation of individual atoms in a microtrap. Blue detuned light is used in order to ensure that only one of the collision partners is lost from the trap. We obtain a 91% loading efficiency of single 85Rb atoms. This can be achieved within a total preparation time of 542 ms. A numerical model of the process quantitatively agrees with the experiment giving an in-depth understanding of the dynamics of the process and allowing us to identify the factors that still limit the loading efficiency. The fast loading time in combination with the high efficiency may be sufficient for loading quantum registers at the size required for competitive quantum computing.

Dynamics of two atoms undergoing light-assisted collisions in an optical microtrap

We study the dynamics of atoms in optical traps when exposed to laser cooling light that induces light-assisted collisions. We experimentally prepare individual atom pairs and observe their evolution. Due to the simplicity of the system (just two atoms in a microtrap) we can directly simulate the pairs dynamics, thereby revealing detailed insight into it. We find that often only one of the collision partners gets expelled, similar to when using blue detuned light for inducing the collisions. This enhances schemes for using light-assisted collisions to prepare individual atoms and affects other applications as well.

Two-Atom Collisions and the Loading of Atoms in Microtraps

We review light assisted collisions in a high-density far-off resonant optical trap (FORT). By tuning the parameters of the light that induces the collisions, the effects of the collisions can be controlled. Trap loss can be suppressed even at high atomic densities, allowing us to count the atoms using fluorescence detection. When only two atoms are trapped, individual loss events reveal new information about the process, and the simplicity of the system allows for a numerical simulation of the dynamics. By optimizing the experimental parameters, we implement an efficient method to prepare single atoms in the FORT. Our methods can be extended to load quantum registers for quantum information processing.

High fidelity source of single atoms in the quantum ground state of optical tweezers

Complete control of individual atoms trapped in far-off resonance optical tweezers is vital for gaining a better understanding of the microscopic world. It will provide a platform with unprecedented flexibility for studying few-body physics, and might lead to new quantum technologies.

Zeeman-insensitive cooling of a single atom to its two-dimensional motional ground state in tightly focused optical tweezers

We combine near--deterministic preparation of a single atom with Raman sideband cooling, to create a push button mechanism to prepare a single atom in the motional ground state of tightly focused optical tweezers. In the 2D radial plane, we achieve a large ground state fidelity for the entire procedure (loading and cooling) of

Single Atoms Preparation Using Light-Assisted Collisions

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In-trap fluorescence detection of atoms in a microscopic dipole trap

0.73, while the ground state occupancy is

Thermally-robust spin correlations between two atoms.

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High fidelity source of a single atom in its 2D quantum ground state

0.88 for realizations with a single atom present. For 1D axial cooling, we attain a ground state fraction of

High Fidelity Preparation of a Single Atom in Its 2D Center of Mass Ground State

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