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Light Modulator (light + modulator)
Selected AbstractsPreparation and optical properties of an all-polymer light modulator using colored N -isopropylacrylamide gel particles in a gel-in-gel systemJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Hiroaki Tsutsui Abstract A novel all-polymer light modulator with a gel-in-gel system was developed. The gel-in-gel system was constructed with colored gel particles responsive to stimuli held independently in another stimuli-nonresponsive gel matrix. Well-known thermoresponsive N -isopropylacrylamide (NIPAM) gel particles containing a pigment were dispersed and fixed in an outer stimuli-nonresponsive gel matrix. When poly(vinyl alcohol),styrylpyridinium (PVA,SbQ) was used for the outer gel matrix, the light modulator showed excellent color-changing properties because the PVA,SbQ matrix was selectively formed around the NIPAM gel particles and the particles exhibited a large volume change in the matrix. The temperature when the outer gel matrix was formed affected the haze of the light modulator. When the outer gel matrix was formed in the swollen state of the NIPAM gels, the haze of a light modulator increased with heating. On the contrary, the haze of a light modulator prepared in the shrunken state of the NIPAM gels decreased with heating. The response time of the color change was less than 1 s. The gel-in-gel system made a very fast macroscopic color change, taking advantage of the fast response of the micrometer-sized gel particles. We believe that a light modulator with a gel-in-gel system may find various applications in optical devices. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2295,2303, 2007 [source] Application of dynamic diffractive optics for enhanced femtosecond laser based cell transfectionJOURNAL OF BIOPHOTONICS, Issue 10-11 2010Maciej Antkowiak Abstract We demonstrate the advantages of a dynamic diffractive optical element, namely a spatial light modulator (SLM) for the controlled and enhanced optoinjection and phototransfection of mammalian cells with a femtosecond light source. The SLM provides full control over the lateral and axial positioning of the beam with sub-micron precision. Fast beam translation enables time-sequenced irradiation, which is shown to enhance the optoinjection efficiency and alleviate the problem of exact beam positioning on the cell membrane. We show that irradiation in three axial positions doubles the number of viably optoinjected cells when compared with a single dose. The presented system also enables untargeted raster scan irradiation which provides a higher throughput transfection of adherent cells at the rate of 1 cell per second. Additionally, fluorescent imaging is used to demonstrate cell selective two-step gene therapy. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Stretching single DNA molecules to demonstrate high-force capabilities of holographic optical tweezersJOURNAL OF BIOPHOTONICS, Issue 4 2010Arnau Farré Abstract The well calibrated force-extension behaviour of single double-stranded DNA molecules was used as a standard to investigate the performance of phase-only holographic optical tweezers at high forces. Specifically, the characteristic overstretch transition at 65 pN was found to appear where expected, demonstrating (1) that holographic optical trap calibration using thermal fluctuation methods is valid to high forces; (2) that the holographic optical traps are harmonic out to >250 nm of 2.1 ,m particle displacement; and (3) that temporal modulations in traps induced by the spatial light modulator (SLM) do not affect the ability of optical traps to hold and steer particles against high forces. These studies demonstrate a new high-force capability for holographic optical traps achievable by SLM technologies. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spatial fluorescence cross-correlation spectroscopy by means of a spatial light modulatorJOURNAL OF BIOPHOTONICS, Issue 5 2008Yoann Blancquaert Abstract Spatial fluorescence cross-correlation spectroscopy is a rarely investigated version of fluorescence correlation spectroscopy, in which the fluorescence signals from different observation volumes are cross-correlated. In the reported experiments, two observation volumes, typically shifted by a few ,m, are produced, with a spatial light modulator and two adjustable pinholes. We illustrated the feasibility and potentiality of this technique by: i) measuring molecular flows, in the range 0.2,1.5 ,m/ms, of solutions seeded with fluorescent nanobeads or rhodamine molecules (simulating active transport phenomenons); ii) investigating the permeability of the phospholipidic membrane of giant unilamellar vesicles versus hydrophilic or hydrophobic molecules (in that case the laser spots were set on both sides of the membrane). Theoretical descriptions are proposed together with a discussion about fluorescence-correlation-spectroscopy-based, alternative methods. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Architecture of Polymeric Superstructures Constructed by Mesoscopically Ordered Cubic LatticesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 4 2003Koji Ishizu Abstract Highly monodisperse crosslinked core-shell polymer microspheres could be prepared easily by introducing special crosslinking reagents into the segregated core in block copolymer assembly films. The crosslinked core was stabilized sterically by highly branched shell chains in solution. These microspheres moved like pseudo-latex. The microspheres formed a lattice with a body-centered cubic (BCC) structure near the overlap threshold (C*). This structure changed to a face-centered cubic (FCC) lattice in the bulk region of the films. Photofunctionalized core-shell microspheres were prepared by introducing dithiocarbamate (DC) groups into shell parts by means of polymer reactions, where DC groups could be propagated using vinyl monomers such as methyl methacrylate (MMA) with living radical mechanism. Polymeric superstructure (three microphase-separated structure) films were constructed by graft copolymerization of MMA initiated with photofunctionalized microspheres such as macroinitiators under UV irradiation, exhibiting self-coloring due to Bragg diffraction. These materials can be used for the construction of optical devices such as for the fabrication of light modulators. Photograph of a solution of the microsphere in MMA. [source] Diffractive optical elements with square concentric rings of equal widthMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010Javier Alda Abstract A diffractive optical element having equal-width concentric square rings is analyzed in this article. This constant width makes possible its realization using spatial light modulators or square pixels phase screens. It allows a simple analytical treatment, and the element is also simulated using the Rayleigh-Sommerfeld approach. An experimental verification of its performance has been compared with the simulated results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:930,934, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25065 [source] Figures of merit of magneto-optic spatial light modulators with magnetophotonic crystalsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2007K. Takahashi Abstract This paper presents the simulated and measured results of two types of one dimensional magnetophotonic crystals (1-D MPC) with single cavity and dual cavity respectively for applcation to thin film type magneto-optic spatial light modulators (MOSLMs). The use of MPC is expected to be effective for thin film type MOSLM, because the apparent Faraday rotation is largely enhanced due to light localization in magnetic defect layer of MPC with a large number of periodic dielectric layers. The complex chracteristics of MPCs are discussed in this paper , Faraday rotation ,F, transmittance T, and figure of merit F = T sin(2,F). It is key point of finding optimal structure of MPC for application of MOSLM to use F, because the T decreased with increase of k, while Faraday rotation ,F increased, indicating that the enhancement of light modulation rate could be achieved by optimizing the figure of merit F defined by F , T ·sin2,F. The maximum F = 13.7 was obtained in dual cavity MPC, while F = 12.5 was obtained in single cavity MPC. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||