Electro-optical Effects In Liquid Crystals Research Articles

LIQUID CRYSTAL BASED OPTICAL SWITCHES

Optical switches using two electro-optical effects in liquid crystals are proposed and investigated for incorporation in a switch matrix for optical networks. These two devices employ selective reflection in cholesteric layers and total reflection at the border between glass and nematic liquid crystal. Prototypes of these switches have been designed and their parameters have been investigated. Initial results suggest the switching contrast ratio of 38.5 and 42 dB, respectively, with insertion loss about 2.3…2.9 dB for polarized light.

Photon spin-to-orbital angular momentum conversion via an electrically tunable q-plate

Exploiting electro-optic effects in liquid crystals, we achieved real-time control of the retardation of liquid-crystal-based q-plates through an externally applied voltage. Electro-optic q-plates can be operated as electrically driven converters of photon spin into orbital angular momentum, enabling a variation of the orbital angular momentum probabilities of the output photons over a time scale of milliseconds.

LIQUID CRYSTAL BASED OPTICAL SWITCHES

Optical switches using two electro-optical effects in liquid crystals are proposed and investigated for incorporation in a switch matrix for optical networks. These two devices employ selective reflection in cholesteric layers and total reflection at the border between glass and nematic liquid crystal. Prototypes of these switches have been designed and their parameters have been investigated. Initial results suggest the switching contrast ratio of 38.5 and 42 dB, respectively, with insertion loss about 2.3…2.9 dB for polarized light.

Liquid Crystal Light Valves with Organic Polymeric Photoconductors

Abstract It has been suggested to use organic polymerle photoconductors in the liquid crystal light valves instead of widely used inorganic ones. Light valves with photoconductive sensibilized polyimides with various types of electro-optical effects in liquid crystals were constructed and tested. The influences of the read-on light regimes and control voltages were analysed. High resolution up to 1500 mm−1 at diffraction efficiency 0.1%, and 40% at space frequencies up to 100 mm−1 were obtained in pulse regimes. Thin holograms can be effectively read on such modulators in reversible mode in real time. The results obtained permit to come to a conclusion about prospects of the organic polymeric photoconductor usage in liquid crystal light valves and applications of the latter for input and output of the optical information.

Liquid-crystal displays: an established example of molecular electronics

Displays using electro-optical effects in liquid crystals are now well established and have permitted the manufacture of many new or improved products. This review examines the underlying physics and chemistry which underpins their use as molecular-electronics devices, describes how they operate and looks at a number of recent applications and possible future developments.

The physics and display applications of liquid crystals

Abstract After a short introduction, the general characteristics of liquid crystals are reviewed, the three main classes of thermotropic liquid crystals are described and the concept of order parameters introduced. The phase behaviour of thermotropic liquid crystals is considered in some detail and the continuum theory, describing the static behaviour of liquid crystals, is introduced. Electro-optical effects in liquid crystals and display construction methods are then covered and the operating principles and performance of dynamic scattering, twisted nematic and dyed phase-change displays are reviewed and compared. Threshold and realignment mechanisms in liquid crystal displays are then treated in some detail followed by a consideration of the physics of their dynamical behaviour and response times. The physical properties governing the design of liquid crystal materials and pleochroic dyes are discussed in relation to display performance. The applications of simple displays are then reviewed and the nee...

"Picture" logic and liquid crystals

An analysis is made of the feasibility of picture informs tion processing with the aid of the electro-optic effects in liquid crystals. The dynamic scattering and the twist effect, which are not greatly affected by external perturbations, can be used in building logic devices which can deal with 10 Boolean algebraic functions at processing rates up to 106 bit/sec. Such devices require no more than 50 W for the optical input, processing, and output of information. The most promising applications of such devices are matrix transformations, filtering of images, etc.

Electro-optical effects in liquid crystals

This review gives information on the electric and optical properties of liquid crystals (LC), and discusses in detail various electro-optical effects in nematic, cholesteric, and smectic LC. Dielectric deformations of LC in electric fields, electrodynamic instabilities, the electromechanical effect, etc., are treated. Special attention is paid to explaining the physical reasons for the change in the optical properties of thin LC films when acted on by an electric potential. The practical applications of LC in electro-optical devices are briefly reviewed.

Электрооптические эффекты в жидких кристаллах

Электрооптические эффекты в жидких кристаллах

Electro-optic effects in liquid crystals

Electro-optic effects in liquid crystals

Electro-optic response times in liquid crystals

The factors governing electrically induced phase transitions and other electro-optic effects in liquid crystals are discussed and experimental results presented. It is shown that by suitably tailoring materials response times of the order of microseconds can be achieved.