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

Optically controlled grippers for manipulating micron-sized particles

Author(s): Graham Gibson, Louise Barron, Fiona Beck, Graeme Whyte and Miles Padgett

Abstract:

“We report the development of a joystick controlled gripper for the real-time manipulation of micron-sized objects, driven using holographic optical tweezers (HOTs). The gripper consists of an arrangement of four silica beads, located in optical traps, which can be positioned and scaled in order to trap an object indirectly. The joystick can be used to grasp, move (lateral or axial), and change the orientation of the target object. The ability to trap objects indirectly allows us to demonstrate the manipulation of a strongly scattering micron-sized metallic particle.”

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Publication:New Journal of Physics
Issue/Year: New J. Phys. 9 14, Jan. 2007
DOI: 10.1088/1367-2630/9/1/014

Automated trapping, assembly, and sorting with holographic optical tweezers

Author(s): Stephen C. Chapin, Vincent Germain, and Eric R. Dufresne

Abstract:

“We combine real-time feature recognition with holographic optical tweezers to automatically trap, assemble, and sort micron-sized colloidal particles. Closed loop control will enable new applications of optical micromanipulation in biology, medicine, materials science, and possibly quantum computation.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 26, pp. 13095-13100 , 2006
DOI: 10.1364/OE.14.013095

Reverse orbiting of microparticles in optical vortices

Author(s): A. Jesacher, S. Fürhapter, C. Maurer, S. Bernet, and M. Ritsch-Marte

Abstract:

“We report the observation of particles trapped at an air-water surface orbiting in a reverse direction with respect to the orbital angular momentum of the light field. The effect is explained by a combination of asymmetric particle shape and confinement of the particle on the 2D air-water interface. The experiment highlights the strong influence of the particle shape on the momentum transfer, an effect that is often not considered in optical trapping experiments.”

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Publication: Optics Letters
Issue/Year: Optics Letters, Vol. 31, Issue 19, pp. 2824-2826
DOI: 10.1364/OL.31.002824

Algorithm for computing holographic optical tweezers at video rates

Author(s): Mario Montes-Usategui, Encarnación Pleguezuelos, Jordi Andilla, Estela Martín-Badosa, and Ignacio Juvells

Abstract:

“Digital holography enables the creation of multiple optical traps at arbitrary three-dimensional locations and spatial light modulators permit updating those holograms at video rates. However, the time required for computing the holograms makes interactive optical manipulation of several samples difficult to achieve. We introduce an algorithm for computing holographic optical tweezers that is both easy to implement and capable of speeds in excess of 10 Hz when running on a Pentium IV computer. A discussion of the pros and cons of the algorithm, a mathematical analysis of the efficiency of the resulting traps, as well as results of the three-dimensional manipulation of polystyrene micro spheres are included.”

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Publication: SPIE Digital Library
Issue/Year: Proceedings Volume 6326, Optical Trapping and Optical Micromanipulation III; 63262X (2006)
DOI: 10.1117/12.680504

Design of a low-cost interactive holographic optical tweezers system

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

Abstract:

“The paper describes the design of an inexpensive holographic optical tweezers setup. The setup is accompanied by software that allows real-time manipulation of the sample and takes into account the experimental features of the setup, such as aberration correction and LCD modulation. The LCD, a HoloEye LCR-2500, is the physical support of the holograms, which are calculated using the fast random binary mask algorithm. The real-time software achieves 12 fps at full LCD resolution (including aberration correction and modulation) when run on a Pentium IV HT, 3.2 GHz computer.”

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Publication: SPIE Proceedings
Issue/Year: Proc. SPIE 6326, 63262Q (2006)
DOI: 10.1117/12.680593

Direct observation of Gouy phase shift in a propagating optical vortex

Author(s): Junichi Hamazaki, Yuriya Mineta, Kazuhiro Oka, and Ryuji Morita

Abstract:

“Direct observation of Gouy phase shift on an optical vortex was presented through investigating the intensity profiles of a modified LGpm beam with an asymmetric defect, around at the focal point. It was quantitatively found that the rotation profile of a modified LGpm beam manifests the Gouy phase effect where the rotation direction depends on only the sign of topological charge m. This profile measurement method by introducing an asymmetric defect is a simple and useful technique for obtaining the information of the Gouy phase shift, without need of a conventional interference method. In addition, the 3-dimernsional trajectory of the defect was found to describe a uniform straight line.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 18, pp. 8382-8392, 2006
DOI: 10.1364/OE.14.008382
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