We present recent progress towards building a neutral atom quantum computer. We use a new design for a blue-detuned optical lattice to trap single Cs atoms. The lattice is created using a combination of diffractive elements and acousto-optic deflectors (AODs) which give a reconfigurable set of cross-hatched lines. By using AODs, we can vary the number of traps and size of the trapping regions as well as eliminate extraneous traps in Talbot planes. Since this trap uses blue-detuned light, it traps both ground state atoms and atoms excited to the Rydberg state; moreover, by tuning the size of the trapping region, we can make the traps “magic” for a selected Rydberg state. We use an optical tweezer beam for atom rearrangement. When loading atoms into the array, trap sites randomly contain zero or one atoms. Atoms are then moved between different trapping sites using a red-detuned optical tweezer. Optimal atom rearrangement is calculated using the “Hungarian Method”. These rearrangement techniques can be used to create defect-free sub-lattices. Lattice atoms can also be used as a reservoir for a set of selected sites. This allows quick replacement of atoms, and increased data rate, without reloading from a MOT.
An efficient 2D array of blue-detuned optical traps
We demonstrate a 2D lattice of blue-detuned optical traps which uses laser power efficiently, is tolerant to perturbations in beam alignment, and is insensitive to interferometric phases. Blue traps have several advantages over red traps despite requir-
ing a more complicated beam geometry. Since atoms in a blue trap sit at
an intensity minimum, Stark shift noise and site-to-site calibrations are
minimized. However, constructing a blue lattice which efficiently con-
verts laser power into trap depth, is challenging. For example, a lattice
of bottle beams is inefficient because neighboring sites are separated by
two walls, limiting the number of traps that can be formed. An array of
tightly spaced Gaussian beams is a more efficient blue trap, but the trap
potentials are susceptible to alignment perturbations. We demonstrate
an array which uses diffractive optical elements to create a cross-hatched
pattern of lines in the focal region where the atoms are trapped in up to
121 sites. This "line array" is almost twice as efficient as the Gaussian
beam array and is more resilient to perturbations in beam alignment.
- Award ID(s):
- 1720220
- Publication Date:
- NSF-PAR ID:
- 10064297
- Journal Name:
- Bulletin American Physical Society, DAMOP 2018
- Volume:
- 63
- Issue:
- 5
- Page Range or eLocation-ID:
- T01 85
- Sponsoring Org:
- National Science Foundation
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