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

Dark-hollow optical beams with a controllable shape for optical trapping in air

Author(s):

Porfirev, A. P. & Skidanov, R. V.

Abstract:

“A technique for generating dark-hollow optical beams (DHOBs) with a controllable cross-sectional intensity distribution is proposed and studied both theoretically and experimentally. Superimposed Bessel beams were used to generate such DHOBs. Variation of individual beam parameters enables the generation of Bessel-like non-diffracting beams. This technique allows the design of transmission functions for elements that shape both non-rotating and rotating DHOBs. We demonstrate photophoresis-based optical trapping and manipulation of absorbing air-borne nanoclusters with such beams.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 23; Number 7; Pages 8373; 2015
DOI: 10.1364/oe.23.008373

Optically driven pumps and flow sensors for microfluidic systems

Author(s): H Mushfique, J Leach, R Di Leonardo, M J Padgett, J M Cooper

Abstract:

“This paper describes techniques for generating and measuring fluid flow in microfluidic devices. The first technique is for the multi-point measurement of fluid flow in microscopic geometries. The flow sensing method uses an array of optically trapped microprobe sensors to map out the fluid flow. The optical traps are alternately turned on and off such that the probe particles are displaced by the flow of the surrounding fluid and then retrapped. The particles’ displacements are monitored by digital video microscopy and directly converted into velocity field values. The second is a method for generating flow within a microfluidic channel using an optically driven pump. The optically driven pump consists of two counter-rotating birefringent vaterite particles trapped within a microfluidic channel and driven using optical tweezers. The transfer of spin angular momentum from a circularly polarized laser beam causes the particles to rotate at up to 10 Hz. The pump is shown to be able to displace fluid in microchannels, with flow rates of up to 200 m-3 s-1 (200 fL s-1). In addition a flow sensing method, based upon the technique mentioned above, is incorporated into the system in order to map the magnitude and direction of fluid flow within the channel.”

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Publication: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
Issue/Year: Journal of Mechanical Engineering Science, Volume 222, Number 5 / 2008, Pages 829-837
DOI: 10.1243/09544062JMES760

Optical tweezers of programmable shape with transverse scattering forces

Author(s): Alexander Jesacher, Christian Maurer, Severin Fuerhapter, Andreas Schwaighofer, Stefan Bernet, Monika Ritsch-Marte

Abstract:

“We propose a non-holographic method to create line traps of arbitrary shape in the sample plane. Setting the phase gradient along theses lines gives control over the transverse forces acting on the confined particles. Phase structures, displayed on a spatial light modulator, are optically processed by a spiral phase filter and imaged onto the object plane of a microscope objective. The resulting bright line structures can be used to trap microparticles. Additionally, they exert transverse scattering forces, which can be exploited for inducing orbital motions or for creating “attracting” or “repelling” points, respectively. We give theoretical and experimental evidence that these scattering forces are proportional to the curvature of the line tweezers.”

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Publication:Optics Communications
Issue/Year: Optics Communications, Volume 281, Issue 8, 15 April 2008, Pages 2207-2212
DOI: 10.1016/j.optcom.2007.12.042

Full phase and amplitude control of holographic optical tweezers with high efficiency

Author(s): Alexander Jesacher, Christian Maurer, Andreas Schwaighofer, Stefan Bernet, and Monika Ritsch-Marte

Abstract:

“Recently we demonstrated the applicability of a holographic method for shaping complex wavefronts to spatial light modulator (SLM) systems. Here we examine the potential of this approach for optical micromanipulation. Since the method allows one to shape both amplitude and phase of a trapping light field independently and thus provides full control over scattering and gradient forces, it extends the possibilities of commonly used holographic tweezers systems. We utilize two cascaded phase-diffractive elements which can actually be display side-by-side on a single programmable phase modulator. Theoretically the obtainable light efficiency is close to 100%, in our case the major practical limitation arises from absorption in the SLM. We present data which demonstrate the ability to create user-defined “light pathways” for microparticles driven by transverse radiation pressure.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 16, Issue 7, pp. 4479-4486, 2008
DOI: 10.1364/OE.16.004479

Holographic optical tweezers with real-time hologram calculation using a phase-only modulating LCOS-based SLM at 1064 nm

Author(s): Andreas Hermerschmidt, Sven Krüger, Tobias Haist, Susanne Zwick, Michael Warber, Wolfgang Osten

Abstract:

“We present a method that enables the generation of arbitrary positioned dual-beam traps without additional hardware in a single-beam holographic optical tweezers setup. By this approach stable trapping at low numerical aperture and long working distance is realized with an inverse standard research microscope. Simulations and first experimental results are presented. Additionally we present first steps towards using the method to realize a holographic 4pi-microscope. We will also give a detailed analysis of the phase-modulating properties and especially the spatial-frequency dependent diffraction efficiency of holograms reconstructed with the phase-only LCOS spatial light modulator used in our system. Finally, accelerated hologram optimization based on the iterative Fourier transform algorithm is done using the graphics processing unit of a consumer graphics board.”

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Publication: SPIE Digital Library
Issue/Year: SPIE Proceedings, Vol. 6905, 690508 (2008),
DOI: 10.1117/12.764649

Hypergeometric-Gaussian modes

Author(s): Ebrahim Karimi, Gianluigi Zito, Bruno Piccirillo, Lorenzo Marrucci, and Enrico Santamato

Abstract:

“We studied a novel family of paraxial laser beams forming an overcomplete yet nonorthogonal set of modes. These modes have a singular phase profile and are eigenfunctions of the photon orbital angular momentum. The intensity profile is characterized by a single brilliant ring with the singularity at its center, where the field amplitude vanishes. The complex amplitude is proportional to the degenerate (confluent) hypergeometric function, and therefore we term such beams hypergeometric-Gaussian (HyGG) modes. Unlike the recently introduced hypergeometric modes [Opt. Lett. 32, 742 (2007)], the HyGG modes carry a finite power and have been generated in this work with a liquid-crystal spatial light modulator. We briefly consider some subfamilies of the HyGG modes as the modified Bessel Gaussian modes, the modified exponential Gaussian modes, and the modified Laguerre-Gaussian modes.”

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Publication: Optics Letters
Issue/Year: Optics Letters, Vol. 32, Issue 21, pp. 3053-3055
DOI: 10.1364/OL.32.003053

HoloTrap: Interactive hologram design for multiple dynamic optical trapping

Author(s): E. Pleguezuelos, A. Carnicer, J. Andilla, E. Martín-Badosa, M. Montes-Usategui

Abstract:

“This work presents an application that generates real-time holograms to be displayed on a holographic optical tweezers setup; a technique that allows the manipulation of particles in the range from micrometres to nanometres. The software is written in Java, and uses random binary masks to generate the holograms. It allows customization of several parameters that are dependent on the experimental setup, such as the specific characteristics of the device displaying the hologram, or the presence of aberrations. We evaluate the software’s performance and conclude that real-time interaction is achieved. We give our experimental results from manipulating 5 μm microspheres using the program.”

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Publication: Computer Physics Communications
Issue/Year: Computer Physics Communications, Volume 176, Issues 11-12, Pages 701-709, (2007)
DOI: 10.1016/j.cpc.2007.03.003

Holografisch generierte Doppelfallen für dreidimensionales Trapping

Author(s): Susanne Zwick, L. He, M. Warber, T. Haist, W. Osten

Abstract:

“In konventionellen optischen Pinzetten ist der axiale Einfang von mikroskopischen Partikeln nur durch starke Fokussierung des Laserstrahls mit einem hochaperturigen Mikroskopobjektiv möglich. Wir stellen ein Verfahren vor, mit dem der axiale Einfang in holografischen Pinzetten auch mit niederaperturigen Objektiven ermöglicht wird.”

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Publication: DGaO Proceedings
ISSN: 1614-8436

Computer generation of optimal holograms for optical trap arrays

Author(s): Roberto Di Leonardo, Francesca Ianni, and Giancarlo Ruocco

Abstract:

“We propose a new iterative algorithm for obtaining optimal holograms targeted to the generation of arbitrary three dimensional structures of optical traps. The algorithm basic idea and performance are discussed in conjunction to other available algorithms. We show that all algorithms lead to a phase distribution maximizing a specific performance quantifier, expressed as a function of the trap intensities. In this scheme we go a step further by introducing a new quantifier and the associated algorithm leading to unprecedented efficiency and uniformity in trap light distributions. The algorithms performances are investigated both numerically and experimentally.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 15, Issue 4, pp. 1913-1922
DOI: 10.1364/OE.15.001913
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