Electro-optical Investigations

Buleva M, Stoimenova M. Electro-optic investigation of oxide suspension. Mechanism of formation of the induced dipole moment. J Colloid Interface Sci 1991 141 426-432. 

C. C. Bowley, A. K. Fontecchio, and G. P. Crawford, Electro-optical investigations of H-PDLCS the effect of monomer functionaUty on display performance, SID Inti. Symp. Digest Tech. Papers, 30, 958 (1999). 

I. Wirth, W. Weissflog, Structural and electro-optical investigations ofthe smectic phase of chlorine-substituted banana-shaped compounds, Liq. Cryst. 26 (1999) 401. 

Figure 13.4. Electro-optical investigations at 2 Hz on a chiral smectic C elastomer. An unsymmetrical switching behavior is observed due to the network conformation (reproduced with permission from [25]).

Optical and electro-optical behavior of side-chain liquid crystalline polymers are described 350-351>. The effect of flexible siloxane spacers on the phase properties and electric field effects were determined. Rheological properties of siloxane containing liquid crystalline side-chain polymers were studied as a function of shear rate and temperature 352). The effect of cooling rate on the alignment of a siloxane based side-chain liquid crystalline copolymer was investigated 353). It was shown that the dielectric relaxation behavior of the polymers varied in a systematic manner with the rate at which the material was cooled from its isotropic phase. 

An LCD is a ubiquitous electronic display. Now, it is widely distributed among human daily life, like mobile phones, TV, and personal computers. The LCD has, however, a drawback, i.e., slower response than a plasma display or an electroluminescene display. Recently we have first succeeded in combination of a nanoparticle technology with the LCD technology, which realized fast response of the LCD [45,235,236]. Thus we have found a phenomenon, i.e., a frequency modulation of the LCD doped with metallic nanoparticles. Since the frequency modulation, or electro-optic property depends on the kind of metals, we have prepared AgPd bimetallic nanoparticles protected with a typical liquid crystal molecule, 4-cyano-4 -pentylbiphenyl (5CB) to investigate the electro-optic property [45,235,236]. 

Although phase behavior is comparable for both HDDA and PPDA monomer mixtures, the electro-optic properties may behave quite differently. It has been shown previously that the polymer can considerably change PSFLC properties (1,34), but these changes are not the same for all polymers. To investigate the effects... 

Nowadays a large number of functional crystals belongs to the TTB family and presents electro-optic, ferro- piezo- pyroelectric properties (e g. the well-known barium sodium niobate Ba2NaNb50i5 (BNN)). In this work iron and manganese based Kx(lvr%(]Vr )i-xF3 fluorides (0.4solid state reaction and characterised by different diffraction techniques in order to investigate their crystalline stmcture. 

Electro-optical effects (Stark effects) of CdS nanocrystallites were investigated 107,108,109... 

The formation of boundary layers at the surface interface between semiconductor and gas influences also the luminescence and the electro-optical qualities of semiconductors. These effects offer interesting possibilities for studying experimentally the mechanism of chemisorption, the stationary state of chemisorption, and electron defects in the catalyst during catalysis. Experiments along this line have been carried out by some investigators (40,41) who have studied in a qualitative way the factors influencing the oxidation of phenols catalyzed by zinc oxide under the influence of light. Further work on this subject is desirable. 

Electro-optic effects induced by doping liquid crystals with one-dimensional metal nanoparticles were not only investigated in standard electro-optic test cells, but also in costume-made cells consisting of a thin layer of liquid crystal either deposited onto a thin film of alumina with embedded GNRs [443], or using rubbed polyimide alignment layers modified with solution-cast GNR [444]. In both cases, surface plasmon resonance frequencies of the GNR integrated into these liquid crystal cells could be electrically controlled. 

Haase and co-workers investigated electro-optic and dielectric properties of ferroelectric liquid crystals doped with chiral CNTs [495, 496]. The performance of the doped liquid crystal mixture was greatly affected even by a small concentration of CNTs. The experimental results were explained by two effects (1) the spontaneous polarization of the ferroelectric liquid crystal is screened by the 7t-electron system of the CNT and (2) the CNT 7i-electrons trap ionic impurities, resulting in a significant modification of the internal electric field within liquid crystal test cells. 

The electrical characterization of polar media is crucial to investigate their suitability for ferroelectric memories, piezo- or pyroelectric devices and many other ferroelectric applications (see Chapter 3). Optical characterization of polar media is fundamental to investigate their ser-vicability for electro-optic devices or applications in the field of nonlinear optics (see Chapter 4). Additionally there are intentions to characterize polar media with a combination of both, electrical and optical methods, such as to understand ferroelectric phenomena that are influenced by the action of light. 

When investigating the polar structure by photo-induced light scattering we assume that the largest contribution to the initial optical noise is due to diffraction of the pump beam on optical inhomogeneities located at boundaries of ferroelectric domains [9], Figure 9.12 illustrates this concept schematically. Internal electric fields Ei (random fields) yield local perturbations 5n of the index of refraction via the linear electro-optic effect 5n = - n rssEi. 

Kaino and co-workers [255] have investigated the effect of polymer polydis-persity on electro-optic materials properties. No dependence on polydispersity was observed for guest host materials but for Disperse Red chromophores covalently attached to monodisperse polystyrene weaker absorption tails were observed. This result suggests that chromophore-chromophore interactions are modified by the polymer host. 

Borkovec et al. [59] also reported on a two-stage percolation process for the ME AOT (Aerosol OT, bis(2-ethylhexyl)sodium sulfosuccinate) system AOT-decane-water. The structural inversions were investigated using viscosity, conductivity, and electro-optical effect measurements. The viscosity results showed a characteristic profile with two maxima, which was interpreted as evidence for two symmetrical percolation processes an oil percolation on the water-rich side of the phase diagram and a water percolation process on the oil-rich side. 

Lilhe JJ, Thomas MA, Denis KA, Jokerst NM, Henderson C, Ralph SE (2004) Modal pattern analysis and experimentatal investigation of multimode interferometric sensing a path to fully integrated silicon-CMOS-based chem./bio sensors. Proc Lasers and Electro-Optics Society Annual Meeting -LEOS, pp 352-353... 

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