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

Synthesis of multiple collinear helical modes generated by a phase-only element

Author(s): Jiao Lin, Xiaocong Yuan, Shaohua H. Tao, and Ronald E. Burge

Abstract:

“Phase-only elements are generally more desirable than complex-amplitude-modulated elements not only because of the higher diffraction efficiency but the readier implementation and fabrication. A novel iterative algorithm is proposed for generating multiple helical modes by a single phase-only element. A superposition of four helical modes is demonstrated experimentally by using a spatial light modulator.”

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Publication: Journal of the Optical Society of America A
Issue/Year: JOSA A, Vol. 23, Issue 5, pp. 1214-1218, 2006
DOI: 10.1364/JOSAA.23.001214

Aberration correction in holographic optical tweezers

Author(s): Kurt D. Wulff, Daniel G. Cole, Robert L. Clark, Roberto DiLeonardo, Jonathan Leach, Jon Cooper, Graham Gibson, and Miles J. Padgett

Abstract:

“Holographic or diffractive optical components are widely implemented using spatial light modulators within optical tweezers to form multiple, and/or modified traps. We show that by further modifying the hologram design to account for residual aberrations, the fidelity of the focused beams can be significantly improved, quantified by a spot sharpness metric. However, the impact this improvement has on the quality of the optical trap depends upon the particle size. For particle diameters on the order of 1 µm, aberration correction can improve the trap performance metric, which is the ratio of the mean square displacement of a corrected trap to an uncorrected trap, in excess of 25%, but for larger particles the trap performance is not unduly affected by the aberrations typically encountered in commercial spatial light modulators.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 9, pp. 4169-4174, 2006
DOI: 10.1364/OE.14.004169

Holographic optical trapping of aerosol droplets

Author(s): D. R. Burnham and D. McGloin

Abstract:

“We demonstrate the use of holographic optical tweezers for trapping particles in air, specifically aerosol droplets. We show the trapping and manipulation of arrays of liquid aerosols as well as the controlled coagulation of two or more droplets. We discuss the ability of spatial light modulators to manipulate airborne droplets in real time as well as highlight the difficulties associated with loading and trapping particles in such an environment. We conclude with a discussion of some of the applications of such a technique.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 9, pp. 4175-4181, 2006
DOI: 10.1364/OE.14.004175

Fast generation of holographic optical tweezers by random mask encoding of Fourier components

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

Abstract:

“The random mask encoding technique of multiplexing phase-only filters can be easily adapted to the generation of holographic optical tweezers. The result is a direct, non-iterative and extremely fast algorithm that can be used for computing arbitrary arrays of optical traps. Additional benefits include the possibility of modifying any existing hologram to quickly add more trapping sites and the inexistence of ghost traps or replicas.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 6, pp. 2101-2107, 2006
DOI: 10.1364/OE.14.002101

Fast digital hologram generation and adaptive force measurement in liquid-crystal-display-based holographic tweezers

Author(s): Marcus Reicherter, Susanne Zwick, Tobias Haist, Christian Kohler, Hans Tiziani, and Wolfgang Osten

Abstract:

“Computer-generated holograms in conjunction with spatial light modulators (SLMs) offer a way to dynamically generate holograms that are adapted to specific tasks. To use the full dynamic capability of the SLM, the hologram computation should be very fast. We present a method that uses the highly parallel architecture of a consumer graphics board to compute analytical holograms in video real time. A precice characterization of the SLM (Holoeye LC-R-2500) and the adaption of its settings to our near-infrared application is necessary to guarantee an efficient hologram reconstruction. The benefits of a fast computation of adapted holograms and the application of an efficient SLM are demonstrated by measuring the trapping forces of holographic tweezers.”

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Publication: Applied Optics
Issue/Year: Applied Optics, Vol. 45, Issue 5, pp. 888-896, 2006
DOI: 10.1364/AO.45.000888