arXiv subjects

Jai-Min Choi

Publications and source records attributed to Jai-Min Choi.

6 recordsLinked to original sources

arXiv2015

Tuning the Stiffness Asymmetry of Optical Tweezers via Polarization Control

Optical tweezers that utilize a highly focused, linearly polarized laser beam exhibit strong trap stiffness asymmetry, which originates from the anisotropic field distribution in the transverse plane. Based on the previous study of polarization-dependent focused field distribution, we explore its manifestation in optical trap in terms of trap stiffness asymmetry. Our results demonstrate that polarization control provides a versatile tuning knob for tailoring optical potential landscape even in case of a strongly modified focused field in the presence of dielectric spheres larger than the wavelength of a trap beam.

physics.optics↗

arXiv2015

Investigation of Polarization-Dependent Optical Force in Optical Tweezers using Generalized Lorenz-Mie Theory

In vectorial diffraction theory, tight focusing of a linearly polarized laser beam produces an anisotropic field distribution around the focal plane. We present a numerical investigation of the electromagnetic field distribution of a focused beam in terms of the input beam polarization state and the associated effects on the trap stiffness asymmetry of optical tweezers. We also explore the symmetry change of a polarization-dependent optical force due to the electromagnetic field redistribution by the presence of dielectric spheres of selected diameters ranging from the Rayleigh scattering regime to the Mie scattering regime.

physics.optics↗

arXiv2011

Direct Observation and Analysis of Spin Dependent Transport of Single Atoms in a 1D Optical Lattice

We have directly observed spin-dependent transport of single cesium atoms in a 1D optical lattice. A superposition of two circularly polarized standing waves is generated from two counter propagating, linearly polarized laser beams. Rotation of one of the polarizations by $π$ causes displacement of the $σ^{+}$- and $σ^{-}$-lattices by one lattice site. Unidirectional transport over several lattice sites is achieved by rotating the polarization back and forth and flipping the spin after each transport step. We have analyzed the transport efficiency over 10 and more lattice sites, and discussed and quantified relevant error sources.

quant-ph↗

arXiv2009

Imprinting Patterns of Neutral Atoms in an Optical Lattice using Magnetic Resonance Techniques

We prepare arbitrary patterns of neutral atoms in a one-dimensional (1D) optical lattice with single-site precision using microwave radiation in a magnetic field gradient. We give a detailed account of the current limitations and propose methods to overcome them. Our results have direct relevance for addressing of planes, strings or single atoms in higher dimensional optical lattices for quantum information processing or quantum simulations with standard methods in current experiments. Furthermore, our findings pave the way for arbitrary single qubit control with single site resolution.

quant-ph↗

arXiv2009

Microwave Control of Atomic Motion in Optical Lattices

We control the quantum mechanical motion of neutral atoms in an optical lattice by driving microwave transitions between spin states whose trapping potentials are spatially offset. Control of this offset with nanometer precision allows for adjustment of the coupling strength between different motional states, analogous to an adjustable effective Lamb-Dicke factor. This is used both for efficient one-dimensional sideband cooling of individual atoms to a vibrational ground state population of 97%, and to drive coherent Rabi oscillation between arbitrary pairs of vibrational states. We further show that microwaves can drive well resolved transitions between motional states in maximally offset, shallow lattices, and thus in principle allow for coherent control of long range quantum transport.

quant-ph↗

arXiv2009

Quantum Walk in Position Space with Single Optically Trapped Atoms

The quantum walk is the quantum analogue of the well-known random walk, which forms the basis for models and applications in many realms of science. Its properties are markedly different from the classical counterpart and might lead to extensive applications in quantum information science. In our experiment, we implemented a quantum walk on the line with single neutral atoms by deterministically delocalizing them over the sites of a one-dimensional spin-dependent optical lattice. With the use of site-resolved fluorescence imaging, the final wave function is characterized by local quantum state tomography, and its spatial coherence is demonstrated. Our system allows the observation of the quantum-to-classical transition and paves the way for applications, such as quantum cellular automata.

quant-ph↗