Estimation and Compensation of aberrations in Spatial Light Modulators

February, 2011

Author(s): Augusto Arias and Roman Castaneda

Abstract:

“The spatial light modulator (SLM) Holoeye LC-R720 is based on LCoS (Liquid Crystal on Silicon) technology. Due to the induced curvatures on the silicon plate by the production process, there are static aberrations in the wave-fronts modified by the SLM. In order to calculate the aberrated wave-front we used phase-shifting interferometry, an optimization algorithm for far field propagation, and the geometric characterization of the focal spot along the caustic. Zernike polynomials were used for expanding and comparing the wave-fronts. The aberration compensation was carried out by displaying the conjugated transmittance on the SLM. The complexity of the experimental setup and the requirements of the digital processing of each estimation method were comparatively analyzed.”

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Publication: Journal of Physics: Conference Series, (free download)

Issue/Year/DOI: J. Phys.: Conf. Ser., Volume 274, 012060, (2011)
doi:10.1088/1742-6596/274/1/012060


Materials for an Updatable Holographic 3D Display

May, 2010

Author(s): Cory W. Christenson, Pierre-Alexandre Blanche, Savas Tay, Ram Voorakaranam, Tao Gu, Weiping Lin, Peng Wang, Michiharu Yamamoto, Jayan Thomas, Robert A. Norwood, and Nasser Peyghambarian

Abstract:

“Holography is a powerful technique for providing high-resolution, realistic three-dimensional (3D) images without the need for special eyewear. A material that takes full advantage of the potential of holography, including updatability, has not existed. Here, the first updatable holographic 3D display based on a photorefractive polymer is summarized. The performance characteristics of these materials are measured, and how they relate to the development of additional display enhancements such as pulsed writing, white light viewing, and large viewing angle, are discussed.”

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Publication: Journal of Display Technology – via IEEE Xplore (subscription required)

Issue/Year/DOI: Journal of Display Technology, Issue: 99, pp1-7, (2010)
DOI: 10.1109/JDT.2010.2046620


Plasmid copy number noise in monoclonal populations of bacteria

January, 2010

Author(s): Jérôme Wong Ng, Didier Chatenay, Jérôme Robert, Michael Guy Poirier

Abstract:

“Plasmids are extra chromosomal DNA that can confer to their hosts’ supplementary characteristics such as antibiotic resistance. Plasmids code for their copy number through their own replication frequency. Even though the biochemical networks underlying the plasmid copy number (PCN) regulation processes have been studied and modeled, no measurement of the heterogeneity in PCN within a whole population has been done. We have developed a fluorescent-based measurement system, which enables determination of the mean and noise in PCN within a monoclonal population of bacteria. Two different fluorescent protein reporters were inserted: one on the chromosome and the other on the plasmid. The fluorescence of these bacteria was measured with a microfluidic flow cytometry device. We show that our measurements are consistent with known plasmid characteristics. We find that the partitioning system lowers the PCN mean and standard deviation. Finally, bacterial populations were allowed to grow without selective pressure. In this case, we were able to determine the plasmid loss rate and growth inhibition effect.”

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Publication: Physical Review E, (subscription required)

Issue/Year/DOI: Phys. Rev. E, Volume 81, Issue 1, 011909 (2010)
DOI:10.1103/PhysRevE.81.011909


Microdisplays in holographic mastering applications

May, 2009

Author(s): Sven Plöger, Sven Krüger, Stefan Osten, Günther Wernicke

Abstract:

“We demonstrate implementation and performance of microdisplay systems based on liquid-crystal technology in a variety of applications in holographic mastering. These displays can encode 2D objects information in grey scale or address holographic patterns in amplitude or phase. The main advantage is here to address any content dynamically with typically 60 Hz. Furthermore they show a resolution up to 1920×1200 pixels with a pixel size as small as 6.4 microns. Therefore they are extremely suitable for a dynamic or multi-exposure mastering process, to incorporate image content, phase-encode objects or any holographic features. This technology is already being used in holographic security applications as well as in commercial and display holography. We report about a few applications/implementations and show experimental results and performance parameters.

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Publication: SPIE Proceedings, (subscription required)

Issue/Year/DOI: Proc. SPIE, Vol. 7358, 73581H (2009);
doi:10.1117/12.823474


Spatial fluorescence cross-correlation spectroscopy by means of a spatial light modulator

August, 2008

Author(s): Yoann Blancquaert, Jie Gao, Jacques Derouard, Antoine Delon

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 µm, 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 µm/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.”

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Publication: Journal of Biophotonics, (subscription required)

Issue/Year/DOI: Journal of Biophotonics, Volume 1 Issue 5, Pages 408 – 418
doi:10.1002/jbio.200810007


Ultrashort Laguerre-Gaussian pulses with angular and group velocity dispersion compensation

July, 2007

Author(s): I. Zeylikovich, H. I. Sztul, V. Kartazaev, T. Le, and R. R. Alfano

Abstract:

“Coherent optical vortices are generated from ultrashort 6.4 fs pulses. Our results demonstrate angular dispersion compensation of ultrashort 6.4 fs Laguerre-Gaussian (LG) pulses as well as what is believed to be the first direct autocorrelation measurement of 80 fs LG amplified pulses. A reflective-mirror-based 4f-compressor is proposed to compensate the angular and group velocity dispersion of the ultrashort LG pulses.”

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Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 32, Issue 14, pp. 2025-2027 (2007)
doi:10.1364/OL.32.002025


Wavefront correction of spatial light modulators using an optical vortex image

April, 2007

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

Abstract:

“We present a fast and flexible non-interferometric method for the correction of small surface deviations on spatial light modulators, based on the Gerchberg-Saxton algorithm. The surface distortion information is extracted from the shape of a single optical vortex, which is created by the light modulator. The method can be implemented in optical tweezers systems for an optimization of trapping fields, or in an imaging system for an optimization of the point-spread-function of the entire image path.”

Link to Publications Page

Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 15, Issue 9, pp. 5801-5808
doi:10.1364/OE.15.005801


Laguerre-Gaussian supercontinuum

August, 2006

Author(s): H. I. Sztul, V. Kartazayev, and R. R. Alfano

Abstract:

“We show what is believed to be the first coherent white-light optical vortices generated from supercontinuum that have the azimuthally varying phase structure consistent with a monochromatic Laguerre-Gaussian beam. Two methods of Laguerre-Gaussian supercontinuum generation are discussed and contrasted. We use a computer-generated hologram to convert a Gaussian white-light supercontinuum source into Laguerre-Gaussian supercontinuum.”

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Publication: Optics Letters (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 31, Issue 18, pp. 2725-2727
doi:10.1364/OL.31.002725