In situ single-atom array synthesis using dynamic holographic optical tweezers.

Author(s):

Kim, Hyosub and Lee, Woojun and Lee, Han-gyeol and Jo, Hanlae and Song, Yunheung and Ahn, Jaewook

Abstract:

“Establishing a reliable method to form scalable neutral-atom platforms is an essential cornerstone for quantum computation, quantum simulation and quantum many-body physics. Here we demonstrate a real-time transport of single atoms using holographic microtraps controlled by a liquid-crystal spatial light modulator. For this, an analytical design approach to flicker-free microtrap movement is devised and cold rubidium atoms are simultaneously rearranged with 2N motional degrees of freedom, representing unprecedented space controllability. We also accomplish an in situ feedback control for single-atom rearrangements with the high success rate of 99% for up to 10?µm translation. We hope this proof-of-principle demonstration of high-fidelity atom-array preparations will be useful for deterministic loading of N single atoms, especially on arbitrary lattice locations, and also for real-time qubit shuttling in high-dimensional quantum computing architectures.”

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Publication: Nature Communications
Issue/Year: Nature Communications, volume 7, Article number: 13317 (2016)
DOI: 10.1038/ncomms13317

Bessel beams with spatial oscillating polarization

Author(s):

Fu, Shiyao and Zhang, Shikun and Gao, Chunqing

Abstract:

“Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical axis, when propagating in free space. A first holographic axicon (HA) HA1 produces a normal, linearly polarized Bessel beam, which by a second HA2 is converted into the spatial oscillating polarized beam. The theory is briefly discussed, the set-up and the experimental results are presented in detail.”

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Publication: Scientific Reports
Issue/Year: Scientific Reports volume 6, Article number: 30765 (2016)
DOI: 10.1038/srep30765

On the resilience of scalar and vector vortex modes in turbulence

Author(s):

Cox, Mitchell A.; Rosales-Guzman, Carmelo; Lavery, Martin P. J.; Versfeld, Daniel J. & Forbes, Andrew

Abstract:

“Free-space optical communication with spatial modes of light has become topical due to the possibility of dramatically increasing communication bandwidth via Mode Division Multiplexing (MDM). While both scalar and vector vortex modes have been used as transmission bases, it has been suggested that the latter is more robust in turbulence. Using orbital angular momentum as an example, we demonstrate theoretically and experimentally that the crosstalk due to turbulence is the same in the scalar and vector basis sets of such modes. This work brings new insights about the behaviour of vector and scalar modes in turbulence, but more importantly it demonstrates that when considering optimal modes for MDM, the choice should not necessarily be based on their vectorial nature.”

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Publication: Opt. Express
Issue/Year: Opt. Express, Volume 24; Number 16; Pages 18105-18113; 2016
DOI: 10.1364/OE.24.018105

Focusing light into desired patterns through turbid media by feedback-based wavefront shaping

Author(s):

Lipeng Wan and Ziyang Chen and Huiling Huang and Jixiong Pu

Abstract:

“We demonstrate that the focusing of light into desired patterns through turbid media can be realized using feedback-based wavefront shaping. Three desired focused patterns—a triangle, a circle, and a rectangle—are used as examples to study this ability. During the process of modulating scattered light, the Pearson’s correlation coefficient is introduced as a feedback signal. It is found that the speckle field formed by the turbid media gradually transforms into the desired pattern through a process of modulation of the input beam wave front. The proposed approach has potential applications in biomedical treatment and laser material processing.”

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Publication: Applied Physics B
Issue/Year: Applied Physics, B 122, 204 (2016)
DOI: 10.1007/s00340-016-6466-0

Pre-turbulence compensation of orbital angular momentum beams based on a probe and the Gerchberg–Saxton algorithm

Author(s):

Fu, Shiyao; Zhang, Shikun; Wang, Tonglu & Gao, Chunqing

Abstract:

“We propose a scheme that uses a probe Gaussian beam and the Gerchberg-Saxton (GS) algorithm to realize the pre-turbulence compensation of beams carrying orbital angular momentum (OAM). In the experiment, spatial light modulators are utilized to simulate the turbulent atmosphere and upload the retrieval holograms. A probe Gaussian beam is used to detect the turbulence. Then, the retrieval holograms, which can correct the phase distortion of the OAM beams, are obtained by the GS algorithm. The experimental results show that single or multiplexed OAM beams can be compensated well. The compensation performances under different iterations are also analyzed.”

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Publication: Opt. Lett.
Issue/Year: Opt. Lett., Volume 41; Number 14; Pages 3185-3188; 2016
DOI: 10.1364/OL.41.003185

Programmable simulator for beam propagation in turbulent atmosphere

Author(s):

Carolina Rickenstorff, José A. Rodrigo, and Tatiana Alieva

Abstract:

“The study of light propagation though the atmosphere is crucial in different areas such as astronomy, free-space communications, remote sensing, etc. Since outdoors experiments are expensive and difficult to reproduce it is important to develop realistic numerical and experimental simulations. It has been demonstrated that spatial light modulators (SLMs) are well-suited for simulating different turbulent conditions in the laboratory. Here, we present a programmable experimental setup based on liquid crystal SLMs for simulation and analysis of the beam propagation through weak turbulent atmosphere. The simulator allows changing the propagation distances and atmospheric conditions without the need of moving optical elements. Its performance is tested for Gaussian and vortex beams.”

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Publication: Optics Express
Issue/Year: Vol. 24, Issue 9, pp. 10000-10012 (2016)
DOI: 10.1364/OE.24.010000

Experimental demonstration of 3D accelerating beam arrays

Author(s):

Xianghua Yu and Runze Li and Shaohui Yan and Baoli Yao and Peng Gao and Guoxia Han and Ming Lei

Abstract:

“Accelerating beams have attracted much attention in the frontiers of optical physics and technology owing to their unique propagation dynamics of nondiffracting, self-healing, and freely accelerating along curved trajectories. Such behaviors essentially arise from the particular phase factor occurring in their spatial frequency spectrum, e.g., the cubic phase associated to the spectrum of Airy beam. In this paper, we theoretically and experimentally demonstrate a sort of accelerating beam arrays, which are composed of spatially separated accelerating beams.
By superimposing kinoforms of multifocal patterns into the spatial frequency spectrum of accelerating beams, different types of beam arrays, e.g., Airy beam arrays and two-main-lobe accelerating beam arrays, are generated and measured by scanning a reflection mirror near the focal region along the optical axis. The 3D intensity patterns reconstructed from the experimental data present good agreement with the theoretical counterparts. The combination of accelerating beams with optical beam arrays proposed here may find potential applications in various fields such as optical microscopes, optical micromachining, optical trapping, and so on.”

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Publication: Applied Optics
Issue/Year: Applied Optics Volume 55, Issue 11 pp. 3090-3095 (2016)
DOI: 10.1364/ao.55.003090