Electrooptical investigations

The current (third) period, which may be called a colonization, involves wide electrooptical investigations of novel effects in ferroelectric liquid crystals [9, 10] and a study of exotic materials like polymeric and lyotropic mesophases, blue phases in cholesterics, well-ordered smectics, and so on. For conventional (nematic and cholesteric) phases the accent was shifted to the optimization of the material properties for electrooptical devices, though novel phenomena like the supertwist effect [11] and a gamma of linear electrooptical effects [12-14] have also been discovered. 

A sensitive approach for the analysis of molecular structures is the measurement of rotation time constants and optical anisotropy coefficients by relaxation electrooptical methods.The experimental procedure used for electrooptical investigations is relatively simple samples are subjected to electric field pulses, and the response due to field-induced alignment or field-induced reactions is recorded by spectrophotometric techniques. In the dichroism experiments, the absorbance of polarized light is measured under electric field pulses. The measured quantity, linear dichroism (LD), means that anisotropic absorption of plane or linearly polarized light has taken place. 

It might be hoped that the subsequent investigation of LC polymer electrooptics will lead to the discovery of a diversity of interesting features in their electrooptical behaviour 170 17D. 

Synthesis of metal particles has been intensively investigated because metal nanoparticles have been applied to electrooptical devices, electronic devices, imaging materials, catalysis, and so on [16]. Fabrication of nanoparticles becomes one of important topics in nanotechnology. For that purpose, it is neces-... 

Additional Step 12 polymeric nonlinear optical chromophores and electrooptic devices were prepared by the author [1] in earlier investigations. 

Obtaining electrooptical thin films by MOCVD techniques has been less investigated, although volatile oxide precursors—alkoxides or 3-diketonates— exist for nearly all elements. For PbTiOs films titanium isopropoxide has been... 

This concept on cyclopolymerization was effectively applied to the nonconjugated diacetylene more than 35 years ago, which was the current enthusiasm for investigating the electrical, " electrooptical, and optical properties ° of unsaturated polymers existed at the earlier stage. More recently, since various substituted acetylenes have been polymerized to give the 7r-conJugated polymers, the cyclo-... 

An attempt to link covalently an NLO chromophore structurally related to 54 to a polymeric network has been made by introducing a methacrylate group on the donor part of the molecule and a carboxylic acid function on the acceptor one (56) [178]. Copolymerization with glycidyl methacrylate has been successfully carried out, affording a composite polymeric film whose electrooptical properties are under investigation. 

Ferroelectric materials have numerous microelectronics applications, including capacitors (7,2), nonvolatile memory devices (2-4 electrooptic devices 1,4) and many others (5). The ferroelectrics described in this paper are Pb(ZrxTii x)03 (PZT), BaTi03, and YMn03. Here we investigate the use of a photochemical method for the direct deposition of these complex materials. 

Much of what has been said above concerning the electrooptic effect also applies mutatis mutandis to the piezooptic effect (variation of refractive index by external mechanical stress). Due to unavoidable dispersion piezooptic coefficients measured by optical techniques can hardly be related to the low-frequency regime for which the definitions of Sect. 6.3 are intended. Determining these constants quasistatically or at sufficiently low frequencies would involve the measurement of permittivity under mechanical stress. Investigations of this type have been made by the group around Newnham and Cross (Uchino et al. (1980), Rittenmyer et al. (1983), Meng and Cross (1985)). 

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