ELECTRO-OPTIC AND OPTICAL DEVICES

All books, reviews, and entries on CPs describe the potential applications. Chandrasekhar and others ° have reviewed in comprehensive fashion the applications of CPs, including batteries sensors electro-optic and optical devices microwave- and conductivity-based technologies electrochromic devices electrochemomechanical and chemomechanical devices corrosion protection semiconductor, lithography, and electrically related applications— photovoltaics, heterojunction, and photoelectrochemical cells capacitors electrolytic and electroless metal plating CP-based molecular electronic devices catalysis and delivery of drugs and chemicals membranes and LEDs. 

The electro-optic and optical devices based on CPs can be classified into three categories those based on second order NLO properties those based on third order NLO properties those based on properties other than NLO CP-based lasers. The driving forces behind the development of these devices are discussed elsewhere. 

Liquid crystal display systems have been increasingly used in electro-optical devices such as digital watches, calculators, televisions, instmment panels, and displays of various kinds of electronic equipment, ie, lap-top computers and word processors. The dominant reason for thek success is thek extremely low power consumption. Furthermore, the Hquid crystal display systems have been remarkably improved in recent years, and today they have high resolution (more than 300,000 pixels) and full color capabiUty almost equivalent to those of a cathode ray tube. 

On the other hand, fluorine s high electronegativity and its ability to form mostly ionic chemical bonds, provide materials with several useful properties. First, compared to oxides, fluoride compounds have a wide forbidden zone and as a result, have low electroconductivity. In addition, fluorides are characterized by a high transparency in a wide optical range that allows for their application in the manufacturing of electro-optical devices that operate in the UV region [42,43]. 

Electro-optic The liquid crystal plastics exhibit some of the properties of crystalline solids and still flow easily as liquids (Chapter 6). One group of these materials is based on low polymers with strong field interacting side chains. Using these materials, there has developed a field of electro-optic devices whose characteristics can be changed sharply by the application of an electric field. 

Occasionally new pyrotechnic phenomena are discovered (Refs 98,99 124) which may see application in special situations. An example is the devlopment of pulsating burning pyrotechnics which constitute the optical analogue to the familiar whistling compds (Ref 138, Formulas 156—60). Whereas pyrotechnic whistles have a frequency of 2000 to 5000 cps, the new compns bum in the range of 0.1 to 700 cps and are therefore well suited for acquisition by electro-optical devices... 

Photoelectrochemical techniques have been utilized to determine the minority (electron) diffusion length (L) and other electrical parameters of p-ZnTe [125] and p-type Cdi-jcZnjcTe alloys [126]. In the latter case, the results for a series of single crystals with free carrier concentration in the range 10 " -10 cm (L = 2-4 xm, constant Urbach s parameter at ca. 125 eV ) were considered encouraging for the production of optical and electro-optical devices based on heterojunctions of these alloys. 

In recent years advances in the chemistry of leuco dyes have taken place particularly in the areas of structural identification by means of H- and 13C-NMR and selective syntheses of aminoquinones, etc. New applications of leuco quinones such as in electro-optical devices and information recording media have enhanced their importance. In these applications, the chemistry of leuco quinones is interesting mainly due to switching from a colored to a colorless system by a redox process. 

New applications (e.g. demand for fluorescent, pearlescent and other brilliant pigments introduction of photoconductive elements in polymer-based electro-optical devices)... 

Dalton, L. R. Robinson, B. H. Jen, A. K. Y. Steier, W. H. Nielsen, R., Systematic develop ment of high bandwidth, low drive voltage organic electro optic devices and their applications, Opt. Mater. 2003, 21, 19 28... 

Colloidal crysfals can be viewed as the mesoscopic counterpart of atomic or molecular crystals. They have been used to explore diverse phenomena such as crystal growth [52-54] and glass transition [55,56], and have many interesting applications for sensors [57], in catalysis [58,59], advanced coatings [60], and for optical/electro-optical devices for information processing and storage [61,62]. In particular, their unusual optical properties, namely the diffraction of visible light and the existence of a photonic stop band, make them ideal candidates for the development of photonic materials [61,63-66]. They may lead to the fabrication... 

Until recently a general drawback of this passive Q-switching scheme was the difficulty of obtaining an exact synchronization of the giant pulse with other events in more complex experiments. This difficulty does not exist with active Q-switching in which an electro-optic device, e.g. a Kerr-cell or Pockels-cell, is used instead of a dye cell, and one is able to determine exactly the time at which... 

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. 

Warner and co-workers justify the elaborate optical/detection system and the time commitment required per analysis on the basis of the additional sensitivity available using fluorescence detection, and on the multidimensional CD information available. For applications in which two, or more CD active fluorophores may be present, the ability to provide both an excitation and emission FDCD profile for the sample may allow differentiation of the individual components without pre-separation. Replacement of the mechanical mechanism for prism movement with an electro-optical device may improve both the SNR and reduce the time required per sample. These improvements will greatly facilitate general application of this multidimensional approach to FDCD measurements. 

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