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

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.” Link to Publications Page 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

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…

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

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…

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

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.” Link to…

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

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,…

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

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…

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

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…

Sagnac-interferometer-based characterization of spatial light modulators

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.”…

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

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…

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

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…

1 2 3