Dynamic optical manipulation using intensity patterns directly projected by a reflective spatial light modulator

Author(s): S. H. Tao, X.-C. Yuan, H. B. Niu and X. Peng

Abstract:

“We propose a simple method to manipulate microparticles dynamically with intensity-modulated patterns projected by a spatial light modulator (SLM), on which the patterns are controlled by a computer directly. The patterns are intensity–intensity modulated by the SLM without involving any computation or algorithm. With the dynamic patterns we can manipulate particles interactively and visibly by drawing or mouse-dragging pictures or even playing a video file on the computer screen. Experimental observations verified the feasibility of the proposed technique as a simple and direct solution for interactive optical manipulation.”

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Publication: Review of Scientific Instruments, (subscription required)

Issue/Year/DOI: Rev. Sci. Instrum. 76, 056103 (2005);
doi:10.1063/1.1898065

Compensation for pixel-mismatch errors in shift-multiplexed holographic data storage

Author(s): Sungphil Kim, Seok Ho Song, Jideog Kim, and Hong-Seok Lee

Abstract:

“To read out correct data from shift-multiplexed holographic data storage, we propose a novel method of pixel matching by use of a tiny plane-parallel refraction plate placed in the path of converging readout beams. Tilting the refraction plate produces a shift in the lateral position of the readout beam incident upon the holographic storage disk, leading to compensation for pixel-mismatch errors by an improvement in bit-error rate of 3 orders of magnitude.”

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Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 30, Issue 7, pp. 771-773 (2005)
doi:10.1364/OL.30.000771

A single-stage reconfigurable 2-D optical perfect-shuffle network system using multiplexed phase holograms

Author(s): Kyongsik Choi Byoungho Lee

Abstract:

“We propose a single-stage reconfigurable two-dimensional (2-D) optical perfect-shuffle network system (PSNS) using multiplexed phase holograms on one phase-type spatial light modulator (SLM). Phase holograms are used that adopt dynamically combined and multiplexed holograms to implement 2-D perfect shuffling of optical images. Experimentally, we demonstrate the proof-of-principle of the proposed single-stage reconfigurable 2-D optical PSNS using a collimated light source, the multiplexed phase holograms on a phase-type SLM, and a Fourier transform lens.”

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Publication: IEEE, Photonics Technology Letters (subscription required)

Issue/Year/DOI: IEEE, Photonics Technology Letter, Volume: 17, Issue: 3 pp. 687-689 (2005)
DOI: 10.1109/LPT.2004.842327

Structure and scaling of helical modes of light

Author(s): Steven Sundbeck, Ilya Gruzberg, and David G. Grier

Abstract:

“Modes of light that contain topological defects such as screw dislocations can be focused into optical traps with interesting and useful properties. The way in which the intensity distribution within helical modes of light varies with topological charge is discussed, and new scaling predictions for their radial profiles that are consistent with experimental observations are introduced.”

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Publication: Optics Letters (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 30, Issue 5, pp. 477-479
doi:10.1364/OL.30.000477

Vortex knots in light

Author(s): J. Leach, M. R. Dennis, J. Courtial and M. J. Padgett

Abstract:

“Optical vortices generically arise when optical beams are combined. Recently, we reported how several laser beams containing optical vortices could be combined to form optical vortex loops, links and knots embedded in a light beam (Leach et al 2004 Nature 432 165). Here, we describe in detail the experiments in which vortex loops form these structures. The experimental construction follows a theoretical model originally proposed by Berry and Dennis, and the beams are synthesized using a programmable spatial light modulator and imaged using a CCD camera.”

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Publication: New Journal of Physics (free download)

Issue/Year/DOI: New J. Phys. 7, 55 (2005)
doi: 10.1088/1367-2630/7/1/055

Spiral phase contrast imaging in microscopy

Author(s): Severin Fürhapter, Alexander Jesacher, Stefan Bernet, and Monika Ritsch-Marte

Abstract:

“We demonstrate an optical method for edge contrast enhancement in light microscopy. The method is based on holographic Fourier plane filtering of the microscopic image with a spiral phase element (also called vortex phase or helical phase filter) displayed as an off-axis hologram at a computer controlled high resolution spatial light modulator (SLM) in the optical imaging pathway. The phase hologram imprints a helical phase term of the form exp(i ??) on the diffracted light field in its Fourier plane. In the image plane, this results in a strong and isotropic edge contrast enhancement for both amplitude and phase objects.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 13, Issue 3, pp. 689-694
doi:10.1364/OPEX.13.000689

Photoporation and cell transfection using a violet diode laser

Author(s): L. Paterson, B. Agate, M. Comrie, R. Ferguson, T. Lake, J. Morris, A. Carruthers, C. T. Brown, W. Sibbett, P. Bryant, F. Gunn-Moore, A. Riches, and Kishan Dholakia

Abstract:

“The introduction and subsequent expression of foreign DNA inside living mammalian cells (transfection) is achieved by photoporation with a violet diode laser. We direct a compact 405 nm laser diode source into an inverted optical microscope configuration and expose cells to 0.3 mW for 40 ms. The localized optical power density of ~1200 MW/m2 is six orders of magnitude lower than that used in femtosecond photoporation (~104 TW/m2). The beam perforates the cell plasma membrane to allow uptake of plasmid DNA containing an antibiotic resistant gene as well as the green fluorescent protein (GFP) gene. Successfully transfected cells then expand into clonal groups which are used to create stable cell lines. The use of the violet diode laser offers a new and simple poration technique compatible with standard microscopes and is the simplest method of laser-assisted cell poration reported to date.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 13, Issue 2, pp. 595-600
doi:10.1364/OPEX.13.000595

Determination of the phase- and polarization-changing properties of reflective spatial light modulators in one set-up

Author(s): Kay Gastinger, Ola D. Hunderi and Mikael Lindgren.

Abstract:

“The use of liquid crystal spatial light modulators in applications, require good characterization of phase, polarization and amplitude shifting properties. This report presents a new approach for simultaneously characterizing the depolarization and controlling the polarization properties of a reflective twisted nematic liquid crystal spatial light modulator (LC SLM). The SLM was set up as a part of a Michelson interferometer. The phase response was determined by using a piezo-electric actuator for phase stepping in the reference arm. During the polarization measurement the reference beam was removed and the polarization state of the input and output was determined by a polarization state generator (PSG) and a polarization state analyzer (PSA), each consisting of a polarizer and a quarter-wave plate. Hereby, both phase response and polarization control properties could be determined independently in the same measurement configuration simply by changing static polarization components. The systematic rotation of the quarter wave plates of the PSG and the PSA using stepper motors gives out-put data whose Fourier transform in terms of angular frequency components can be used to determine all the elements of the Mueller matrix. The Mueller matrix of a commercial SLM (Holoeye LC-2500) was determined for 17 evenly spaced voltage levels addressed to the SLM.”

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Publication: SPIE Proceedings, (subscription required)

Issue/Year/DOI: Proc. SPIE, Vol. 5618, 174 (2004);
DOI:10.1117/12.578438

Laser beams: Knotted threads of darkness

Author(s): Jonathan Leach, Mark R. Dennis, Johannes Courtial & Miles J. Padgett

Abstract:

“Destructive interference may lead to complete cancellation when light waves travelling in different directions cross, and in three-dimensional space this occurs along lines that are vortices of electromagnetic energy flow. Here we confirm theoretical predictions by experimentally creating combinations of optical laser beams in which these dark threads form stable loops that are linked and knotted.”

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Publication: Nature (subscription required)

Issue/Year/DOI: Nature 432, 165 (11 November 2004)
doi:10.1038/432165a

Assembly of 3-dimensional structures using programmable holographic optical tweezers

Author(s): Gavin Sinclair, Pamela Jordan, Johannes Courtial, Miles Padgett, Jon Cooper, and Zsolt Laczik

Abstract:

“The micromanipulation of objects into 3-dimensional geometries within holographic optical tweezers is carried out using modified Gerchberg-Saxton (GS) and direct binary search (DBS) algorithms to produce the hologram designs. The algorithms calculate sequences of phase holograms, which are implemented using a spatial light modulator, to reconfigure the geometries of optical traps in many planes simultaneously. The GS algorithm is able to calculate holograms quickly from the initial, intermediate and final trap positions. In contrast, the DBS algorithm is slower and therefore used to pre-calculate the holograms, which are then displayed in sequence. Assembly of objects in a variety of 3-D configurations is semi-automated, once the traps in their initial positions are loaded.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 12, Issue 22, pp. 5475-5480
doi:10.1364/OPEX.12.005475