Creating permanent 3D arrangements of isolated cells using holographic optical tweezers

Author(s): Pamela Jordan, Jonathan Leach, Miles Padgett, Paul Blackburn, Neil Isaacs, Mattias Goksör, Dag Hanstorp, Amanda Wright, John Girkin and Jonathan Cooper

Abstract:

“We report the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within a solution comprising monomer precursors. The matrix was then set and after the laser beam was removed, we were able to demonstrate that the structures remained intact for many days. We were also able to demonstrate that, in the presence of appropriate nutrients, the E. coli survived within the gelatin matrix for several days. The technique could have a number of potential future applications, including the arrangement of a variety of different cell types in complex architectures, as motifs for promoting tissue differentiation and growth within the field of cell engineering.”

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Publication: Lab on a Chip (free download)

Issue/Year/DOI: Lab Chip, 2005, 5, 1224-1228
DOI: 10.1039/b509218c

Raman imaging of floating cells

Author(s): Caitriona Creely, Giovanni Volpe, Gajendra Singh, Marta Soler, and Dmitri Petrov

Abstract:

“Raman imaging can yield spatially resolved biochemical information from living cells. To date there have been no Raman images published of cells in suspension because of the problem of immobilizing them suitably to acquire space-resolved spectra. In this paper in order to overcome this problem the use of holographic optical tweezers is proposed and implemented, and data is shown for spatially resolved Raman spectroscopy of a live cell in suspension.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 13, Issue 16, pp. 6105-6110, 2005
DOI: 10.1364/OPEX.13.006105

Femtosecond pulse shaping using a liquid–crystal display: Applications to depth profiling analysis

Author(s): Ota Samek, Vanja Hommes, Roland Hergenröder, Sergei V. Kukhlevsky

Abstract:

“We report on a beam shaping technique for femtosecond laser pulses based on a liquid-crystal display. The system is capable of modifying femtosecond Gaussian beams to a flattop beam. A pattern projected onto liquid-crystal display modifies the incoming Gaussian beam intensity so that flattop intensity profile is obtained. The process is monitored online using a charge-coupled device camera so that the intensity distribution of each pulse is known. An experimental example of the depth profile of a Cr layer on a Si substrate obtained using such a modified beam is presented.”

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Publication: Review of Scientific Instruments
Issue/Year: Rev. Sci. Instrum. 76, 086104 (2005)
DOI: 10.1063/1.1994897

Spiral interferometry

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

Abstract:

“We present a surprising modification of optical interferometry. A so-called spiral phase element in the beam path of a standard microscope results in an interferogram of phase samples, for which the interference fringes have the shape of spirals instead of closed contour lines as in traditional interferograms. This configuration overrides the basic problem of interferometry, i.e., that elevations and depressions cannot be distinguished. Therefore a complete sample profile can be reconstructed from a single exposure, promising, e.g., high-speed metrology with a single laser pulse. The method is easy to implement, it does not require a spatially separated reference beam, and it is optimally stable against environmental noise.”

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Publication: Optics Letters
Issue/Year: Optics Letters, Vol. 30, Issue 15, pp. 1953-1955 (2005)
DOI: 10.1364/OL.30.001953

Encoding fully-complex transmittance with coupled amplitude-phase liquid-crystal modulator

Author(s): Victor M. Arrizón, Luis A. Gonzalez Lopez

Abstract:

“We propose a holographic code for synthesis of fully-complex transmittance, which can be implemented employing a twisted-nematic liquid-crystal display, two linear polarizers, and a He-Ne laser. This simple setup provides a reduced phase range and amplitude modulation with significant variance. Our holographic code efficiently exploits this constrained modulation for the accurate encoding of arbitrary complex transmittance. Two experimental examples illustrate the good performance of the holographic code.”

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Publication: SPIE – Optical Engineering
Issue/Year: Opt. Eng., Vol. 44, 070502 (2005)
DOI: 10.1117/1.1978427

Shadow Effects in Spiral Phase Contrast Microscopy

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

Abstract:

“Recently it has been demonstrated that spatial filtering of images in microscopy with a spiral phase element in a Fourier plane of the optical path results in a strong edge enhancement of object structures. In principle the operation is isotropic, i.e., all phase edges of a sample object are highlighted simultaneously, independent of their local direction. However, here we demonstrate that the symmetry can be broken intentionally by controlling the phase of the central area of a spiral phase hologram, which is displayed at a computer controlled spatial light modulator. This produces an apparent shadow effect which can be rotated at video rate. The resulting relieflike impression of the sample topography with a longitudinal resolution in the subwavelength regime is demonstrated by imaging a standard low contrast test sample consisting of a human cheek cell.”

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Publication: Physical Review Letters
Issue/Year: Phys. Rev. Lett. 94, 233902 (2005)
DOI: 10.1103/PhysRevLett.94.233902

3D interferometric optical tweezers using a single spatial light modulator

Author(s): Ethan Schonbrun, Rafael Piestun, Pamela Jordan, Jon Cooper, Kurt Wulff, Johannes Courtial, and Miles Padgett

Abstract:

“Hexagonal arrays of micron sized silica beads have been trapped in three-dimensions within an optical lattice formed by the interference of multiple plane-waves. The optical lattice design with sharply peaked intensity gradients produces a stronger trapping force than the traditionally sinusoidal intensity distributions of other interferometric systems. The plane waves were generated using a single, phase-only, spatial light modulator (SLM), sited near a Talbot image plane of the traps. Compared to conventional optical tweezers, where the traps are formed in the Fourier-plane of the SLM, this approach may offer an advantage in the creation of large periodic array structures. This method of pattern formation may also be applicable to trapping arrays of atoms.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 13, Issue 10, pp. 3777-3786, 2006
DOI: 10.1364/OPEX.13.003777

Experimental demonstration of holographic three-dimensional light shaping using a Gerchberg–Saxton algorithm

Author(s): Graeme Whyte and Johannes Courtial

Abstract:

“We use a three-dimensional Gerchberg–Saxton algorithm (Shabtay (2003) Opt. Commun. 226 33) to calculate the Fourier-space representation of physically realizable light beams with arbitrarily shaped three-dimensional intensity distributions. From this representation we extract a phase-hologram pattern that allows us to create such light beams experimentally. We show several examples of experimentally shaped light beams.”

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Publication: New Journal of Physics
Issue/Year: New J. Phys. 7 117, 2005
DOI: 10.1088/1367-2630/7/1/117

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