A numerical study of optical switches and modulators based on ferroelectric liquid crystals

Ntogari, Georgia; Tsipouridou, D.; Kriezis, Emmanouil E.

doi:10.1088/1464-4258/7/1/013

Cited by 13 publications

(10 citation statements)

References 13 publications

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“…This principle has been used by Clark and Hand shy 95 for realizing coupling between two slab waveguides, by using a thin layer of surface stabilized ferro-electric liquid-crystal. More detailed simulations for this system have been carried out by Ntogari et al 96 …”

Section: Slab Waveguidesmentioning

confidence: 99%

Liquid-crystal photonic applications

2011

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Abstract. Liquid crystals are nowadays widely used in all types of display applications. However their unique electro-optic properties also make them a suitable material for nondisplay applications. We will focus on the use of liquid crystals in different photonic components: optical filters and switches, beam-steering devices, spatial light modulators, integrated devices based on optical waveguiding, lasers, and optical nonlinear components. Both the basic operating principles as well as the recent state-of-the art are discussed. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).[ DOI: 10.1117/1.3565046] Subject terms: liquid crystals; photonic applications; review; liquid-crystal lasers; spatial light modulators; tunable lenses; nematicons; optical nonlinearity.Paper 100913SSR received Nov. 5, 2010; revised manuscript received Jan. 11, 2011; accepted for publication Jan. 13, 2011; published online Jun. 14, 2011. IntroductionLiquid crystals (LCs) are organic materials that are liquid but that show a certain degree of ordering (positional and/or orientational). With this definition, many materials can be classified as liquid crystals, but the majority of liquid crystals that are used in photonic applications are of the thermotropic type. Thermotropic means that the liquid-crystal phase exists within a certain temperature interval (in contrast to lyotropic materials for which the material is liquid-crystal within a certain concentration range). Various types of thermotropic liquid-crystal materials exist, and many different mesophases have been discovered in the last decades: nematic, smectic A, smectic C, columnar, blue phases, and many many more. The diversity of liquid-crystal materials is huge, but this diversity is even overshadowed by the number of applications in which liquid crystals are used nowadays. The majority of applications are related to informationdisplay applications. Liquid crystals have conquered the major market share in different display application areas: television screens, laptop screens, screens in mobile phones, etc. Only in projection displays does a tough competitor exist, namely microelectromechanical systems or licenced by Texas Instruments: Digital light processing. Organic light emitting diodes (OLEDs) are the obvious next generation technology that could overtake the LC domination, but today OLED displays have not penetrated the market and only the future will tell if they will. In this review article, we will focus on nondisplay applications, but because we cannot go too broad, we restrict ourselves to photonic applications in which the light is actively manipulated by the LC. In this review article, a certain external influence (surface anchoring, electric fields, optical fields) is used to (re)orient the LC in a certain way. In turn, the LC then changes the light that is propagating through it. Of course, as in every review article, it is impossible to list all the fascinating new scientific results or breakthroughs. Therefore, the authors apologize for not i...

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Section: Slab Waveguidesmentioning

confidence: 99%

Liquid-crystal photonic applications

2011

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“…The array of unknowns is extended by . The matrices may be extended in a number of ways, but in order to maintain the symmetry of the right hand side matrix the following form is used (13) Alternatively, the longitudinal components from (7) may be eliminated, resulting in the following quadratic eigenvalue problem: (14) Similarly, via extension, this form may be reduced to a linear eigenvalue problem. Although this second method produces matrices of smaller order, the first method is preferable because the sparsity of the matrices involved is maintained, allowing for a shorter calculation time.…”

Section: Finite-element Mode Solvermentioning

confidence: 99%

“…The optical tensor in the general case can contain up to six nonzero different components. Often the problem is handled with some approximations in terms of the anisotropy or in terms of dimensionality [7], [13], [14]. Transverse anisotropy means that and are zero, while the incorporation of longitudinal anisotropy means that also these terms can be nonzero.…”

mentioning

confidence: 99%

Calculation of Fully Anisotropic Liquid Crystal Waveguide Modes

Beeckman

James

Fernández

et al. 2009

J. Lightwave Technol.

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Abstract-The accurate analysis of optical waveguides is an important issue when designing devices for optical communication. Waveguides combined with liquid crystals have great potential because they allow waveguide tuning over a wide range using low voltages. In this paper, we present calculations that combine an advanced algorithm for calculating liquid crystal behavior and a finite-element mode solver that is able to incorporate the full anisotropy of the materials. Calculation examples demonstrate the validity of our program.Index Terms-Finite-element mode solver, nematic liquid crystal, optical waveguides.

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“…This is often handled with some approximations in terms of the anisotropy or dimensionality. [13][14][15][16] The finite element method has been applied for decades as a versatile numerical tool to obtain approximate solutions to boundary-value problems. Using a finite element scheme offers high accuracy in combination with the flexibility to model arbitrarily curved structures.…”

Section: Introductionmentioning

confidence: 99%

Finite element optical modeling of liquid crystal waveguides

et al. 2011

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Abstract.A finite element modesolver and beam propagation (BPM) algorithm are applied to the optical analysis of liquid crystal waveguides. Both approaches are used in combination with advanced liquid crystal calculations and include a full dielectric tensor in solving the Helmholtz equation to model the liquid crystal behavior properly. Simulation of the beam propagation in a waveguide with tunable liquid crystal cladding layer illustrates the coupling of a Gaussian beam to the fundamental waveguide mode obtained with the modesolver. Excellent quantitative agreement between both approaches illustrates the potential of these methods for the design of advanced devices. The high accuracy of the BPM algorithm for wide angle propagation, essential in the analysis of high index contrast waveguides, is illustrated for angles up to 40 deg. C 2011Society of Photo-Optical Instrumentation Engineers (SPIE).

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A numerical study of optical switches and modulators based on ferroelectric liquid crystals

Cited by 13 publications

References 13 publications

Liquid-crystal photonic applications

Liquid-crystal photonic applications

Calculation of Fully Anisotropic Liquid Crystal Waveguide Modes

Finite element optical modeling of liquid crystal waveguides

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