The Applications and Technology of Phase-Only Liquid Crystal on Silicon Devices

July, 2010

Author(s): Collings, N.; Davey, T.; Christmas, J.; Chu, D.; Crossland, B.

Abstract:

“An introduction to the technology of liquid crystal on silicon (LCOS) devices leads on to a discussion of the application areas which have been and are being opened up by the development of phase-only devices.”

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Publication: Journal of Display Technology, (subscription required)

Issue/Year/DOI: Journal of Display Technology, Vol. 7, Issue 3, pp. 112-119 (2010)
doi:10.1109/JDT.2010.2049337


Nonlinear response studies and corrections for a liquid crystal spatial light modulator

June, 2010

Author(s): RAVINDER KUMAR BANYAL, B. RAGHAVENDRA PRASAD

Abstract:

“The nonlinear response of light transmission characteristics of a liquid crystal (LC) spatial light modulator (SLM) is studied. The results show that the device exhibits a wide range of variations with different control parameters and input settings. Experiments were performed to obtain intensity modulation that is best described by either power-law or sigmoidal functions. Based on the inverse transformation, an appropriate pre-processing scheme for electrically addressed input gray-scale images, particularly important in several optical processing and imaging applications, is suggested. Further, the necessity to compensate the SLM image nonlinearities in a volume holographic data storage and retrieval system is demonstrated.”

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Publication: PRAMANA Journal of Physics (free download)

Issue/Year/DOI: PRAMANA Journal of Physics, Vol. 74, No. 6, June 2010, pp. 961-971


Utilization of the phase flicker of a LCoS Spatial Light Modulator for improved diffractive efficiency

March, 2010

Author(s): Karol Kakarenko, Marcin Zaremba, Izabela Ducin, Michał Makowski, Agnieszka Siemion, Andrzej Siemion, Jarosław Suszek, Maciej Sypek, Dariusz Wojnowski, Zbigniew Jaroszewicz, Andrzej Kołodziejczyk

Abstract:

“The paper presents the observation, measurement and utilization of flickering of phase modulation in time on a high-end Liquid Crystal on Silicon (LCOS) Spatial Light Modulator. The flicker due to binary driving electronics is a negative effect, but can be overcome by appropriate adjustment of phase modulation depth, which results in time-synchronization of peak efficiencies for selected wavelengths. In this work optimal parameters for three wavelengths of primary RGB colors are investigated. The effect is optimal performance of the SLM for full-color dynamic holography.”

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Publication: Photonics Letters of Poland, (free download)

Issue/Year/DOI: Photonics Letters of Poland, Vol 2, No 3, P. 128-130 (2010)
doi:10.4302/plp.2010.3.11


Characterization of a spatial light modulator and its application in phase retrieval

July, 2009

Author(s): C. Kohler, F. Zhang, and Wolfgang Osten

Abstract:

“Recently a phase retrieval method using a movable phase plate as modulator has been proposed [Phys. Rev. A75, 043805 (2007)PLRAAN1050-294710.1103/PhysRevA.75.043805]. This method is applicable to general complex-valued fields and exhibits rapid convergence and high robustness to noise. In this paper, we demonstrate how to use this technique to characterize the phase shifting properties of a liquid-crystal modulator, and in turn we use the characterized modulator as the modulation device in the presented phase retrieval method. The adoption of a dynamic modulator gives a much more robust and flexible setup.”

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Publication: Applied Optics, (subscription required)

Issue/Year/DOI: Applied Optics, Vol. 48, Issue 20, pp. 4003-4008 (2009)
doi:10.1364/AO.48.004003


Poincaré-sphere representation of phase-mostly twisted nematic liquid crystal spatial light modulators

May, 2009

Author(s): V Durán, P Clemente, Ll Martínez-León, V Climent, J Lancis

Abstract:

“We establish necessary conditions in order to build a phase-only wavefront modulation system from a liquid crystal display. These conditions determine the dependence of the polarization state of the light emerging from the display on the addressing gray level. The analysis, which is carried out by means of the coherence-matrix formalism, includes the depolarization properties of the device. Two different types of polarization distributions at the output of the liquid crystal cells are found. This approach is applied to a twisted nematic liquid crystal display. In this case, an optimization algorithm must be designed in order to select the input polarization state that leads to the required distributions. We show that the Poincaré-sphere representation provides a convenient framework to design the optimization algorithm as it allows for a reduced number of degrees of freedom. This feature significantly decreases the computation time. Laboratory results are presented for a liquid crystal on silicon display showing a phase modulation depth greater than 2π rad with an intensity variation lower than 6%. In addition, a hybrid ternary modulation (HTM), an operation regime employed in holographic data storage, is achieved.”

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Publication: Journal of Optics A, (subscription required)

Issue/Year/DOI: J. Opt. A: Pure Appl. Opt. (2009), Opt. 11 085403
doi: 10.1088/1464-4258/11/8/085403


Influence of the incident angle in the performance of Liquid Crystal on Silicon displays

May, 2009

Author(s): A. Lizana, N. Martín, M. Estapé, E. Fernández, I. Moreno, A. Márquez, C. Iemmi, J. Campos, and M. J. Yzuel

Abstract:

“In this paper we experimentally analyze the performance of a twisted nematic liquid crystal on silicon (LCoS) display as a function of the angle of incidence of the incoming beam. These are reflective displays that can be configured to produce amplitude or phase modulation by properly aligning external polarization elements. But we demonstrate that the incident angle plays an important role in the selection of the polarization configuration. We performed a Mueller matrix polarimetric analysis of the display that demonstrates that the recently reported depolarization effect observed in this type of displays is also dependant on the incident angle. ”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 17, Issue 10, pp. 8491-8505 (2009)
doi:10.1364/OE.17.008491


Model-free method for measuring the full Jones matrix of reflective liquid-crystal displays

April, 2009

Author(s): Christian Kohler, Tobias Haist, Wolfgang Osten

Abstract:

“We present a method for measuring all eight parameters (including the signs) of the Jones matrices of liquid-crystal displays. The method can be applied to measure the Jones matrices for all addressable gray levels thus delivering the specifications needed for calculating characteristic curves for arbitrary input and output polarizations. Unlike other approaches, we do not rely on a physical model of the LCD. Thus, it is possible to measure the Jones matrices of a more complex optical system in one step (e.g., when a reflective LCD is used in combination with a beamsplitter). Though the method presented is, in principle, applicable for transmissive and reflective LCDs, calculations and experiments are only shown using the example of a reflective liquid-crystal-on-silicon display. ”

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Publication: SPIE – Optical Engineering, (subscription required)

Issue/Year/DOI: SPIE – Optical Engineering, Vol. 48, 044002 (2009)
doi:10.1117/1.3119309


Sagnac-interferometer-based characterization of spatial light modulators

April, 2009

Author(s): Jian Wei Tay, Michael A. Taylor, Warwick P. Bowen

Abstract:

“A method for characterizing the phase response of spatial light modulators (SLMs) by using a Sagnac interferometer is proposed and demonstrated. The method represents an improvement over conventional diffraction-based or interferometric techniques by providing a simple and accurate phase measurement while taking advantage of the inherent phase stability of a Sagnac interferometer. As a demonstration, the phase response of a commercial liquid crystal on a silicon SLM is characterized and then linearized by using a programmable lookup table. The transverse phase profile over the SLM surface is also measured.”

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Publication: Applied Optics, (subscription required)

Issue/Year/DOI: Applied Optics, Vol. 48, Issue 12, pp. 2236-2242 (2009)
doi:10.1364/AO.48.002236


Systematic errors of an optical encryption system due to the discrete values of a spatial light modulator

February, 2009

Author(s): David S. Monaghan, Unnikrishnan Gopinathan, Damien P. Kelly, Thomas J. Naughton, John T. Sheridan

Abstract:

“An optical implementation of the amplitude encoded double random phase encryption/decryption technique is implemented, and both numerical and experimental results are presented. In particular, we examine the effect of quantization in the decryption process due to the discrete values and quantized levels, which a spatial light modulator (SLM) can physically display. To do this, we characterize a transmissive SLM using Jones matrices and then map a complex image to the physically achievable levels of the SLM using the pseudorandom encoding technique. We present both numerical and experimental results that quantify the performance of the system. ”

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Publication: SPIE – Optical Engineering, (subscription required)

Issue/Year/DOI: Opt. Eng., Vol. 48, 027001 (2009);
doi:10.1117/1.3076208


Time fluctuations of the phase modulation in a liquid crystal on silicon display: characterization and effects in diffractive optics

October, 2008

Author(s): I. Moreno, A. Lizana, A. Márquez, C. Iemmi, E. Fernández, J. Campos, and M. J. Yzuel

Abstract:

“In this paper we provide evidence of the temporal fluctuations of the phase modulation property of a liquid crystal on silicon (LCoS) display, and we analyze its effect when the device is used for displaying a diffractive optical element. We use a commercial twisted nematic LCoS display configured to produce a phase-only modulation, and we provide time resolved measurements of the diffraction efficiency that show rapid fluctuations of the phase modulation, in the millisecond order. We analyze how these fluctuations have to be considered in two typical methods for the characterization of the phase modulation: two beam interference and diffraction from a binary grating. We finally provide experimental results on the use of this device for displaying a computer generated hologram. A reduction of the modulation diffraction efficiency results from the phase modulation fluctuation.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 16, Issue 21, pp. 16711-16722 (2008)
doi:10.1364/OE.16.016711