Materials Literature
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This review summarizes the current state of materials development in nonlinear optics. The relevant properties and important materials constants of current commercial, and new, promising, inorganic and organic molecular and polymeric materials with potential in second and third order NLO applications are presented.
Reactive ion etching of monocrystalline and polycrystalline β-SiC and hydrogenated amorphous a-SiC:H in CF4/O2 mixtures was investigated. The a-SiC:H films, deposited by plasma-enhanced chemical vapor deposition, had the highest etch rate while monocrystalline β-SiC had the lowest etch rate at all compositions of the…
Organic and organometallic stilbazolium cations can be crystallized with various counterions; some of the resulting salts exhibit large SHG powder efficiencies. Approximately linear stilbazolium cations have a greater tendency to crystallize in noncentrosymmetric space groups than do cations with substantial geometric…
Abstract Recent evidence indicates that ferrous carbonate (FeCO3, siderite) plays a critical role in forming corrosion resistant scale. The temperature dependent precipitation kinetics of ferrous carbonate were studied using a powerful new "temperature ramped" approach. The activation energy calculated using a second…
This review gives a brief presentation of the basic concepts and calculation methods of the "anionic group theory" for the NLO effect in borate crystals. On this basis, boron-oxygen groups of various known borate structure types have been classified and systematic calculations were carried out for microscopic second-o…
In the recent past, conjugated polymers were found to have very fast, subpicosecond nonlinear optic response and χ (3) on the order of 10 -9 esu. We have been working on the synthesis of processible conjugated polymers in relation to their electrical conductivity properties. Once processibility was established, we wer…
The promising new electron acceptor, cyclobutenedione, for nonlinear optical materials is proposed instead of conventional nitro (NO 2 ) group. The new acceptor prevents centrosymmetric crystal structures by an introduction of chirality and hydrogen bonding properties into acceptor itself. Asymmetric carbon and hydrog…
Abstract Starting from a "worst case" corrosion rate prediction with the deWaard-Milliams equation, correction factors can be applied to quantify the influence of environmental parameters and of corrosion product scale formed under various conditions. Equations are proposed for each factor. A low temperature scale for…
We consider here a single randomly protonated strand of the conducting polymer polyaniline and show explicitly that the disorder inherent in this system is described by the random-dimer model of Dunlap, Wu, and Phillips [Phys. Rev. Lett. 65, 88 (1990)] with off-diagonal disorder. We demonstrate exactly that the locati…
We report the first well-resolved band-edge luminescence from excitons confined in fully strained SiGe quantum wells grown on Si. At liquid-He temperatures the photoluminescence is due to shallow bound excitons, and in addition to a no-phonon line, phonon-assisted transitions involving TA phonons and Si-Si, Si-Ge, and…
Generation of diamond nuclei has been realized on a silicon mirror surface in plasma chemical vapor deposition. Prior to the normal diamond growth process, a predeposition process of several minutes duration was introduced in which a high methane fraction in the feed gas was used and in which a negative bias voltage w…
In this introductory chapter the concepts of linear and nonlinear polarization are discussed. Both classical and quantum mechanical descriptions of polarizability based on potential surfaces and the "sum over states" formalism are outlined. In addition, it is shown how nonlinear polarization of electrons gives rise to…
Angular distribution patterns of Auger electrons and of photoelectrons from a Cu (001) surface were measured at the same electron kinetic energy. These measurements reveal that the low kinetic energy angular distributions for Cu Auger electrons and Cu 3p(3/2) photoelectrons differ substantially. This direct comparison…
Abstract The effective conductivity of an infinite, random, mono-disperse, hard-sphere suspension is reported for particle to matrix conductivity ratios of ∞, 10 and 0.01 for sphere volume fractions, c, up to 0.6. The conductivities are computed with a method previously described by the authors, which includes both fa…
Abstract Turbidity of quenched polypropylene films was measured as a function of the film thickness and number of times film was recycled. Turbidity τ is defined by τ = (1/ d ) ln ( I o / I t ), where I o and I t are the intensity of the incident and transmitted lights, respectively, and d is the thickness of the samp…
Abstract The crosslinking reactions of ethylene vinyltrimethoxy silane (EVS) copolymers at processing temperatures have been studied. Samples were heated in inert atmosphere with or without water at 130–350°C. The crosslinking reactions were followed by determination of the gel content and by analyzing the structural…
Abstract The scorch property of accelerated sulfur vulcanization of three grades of expoxidized natural rubber (viz. ENR 10, ENR 25, and ENR 50) was studied by using Mooney Shearing Disk Viscometer in the temperature range of 100–180°C. Effects of accelerator types, concentration of accelerator, and carbon black on EN…
Abstract The crosslinking reactions of a new type of polyethylene, an ethylene vinyltrimethoxy silane (EVS) copolymer, when reacted with water has been studied. Samples of EVS were treated in water at 90°C. The kinetics of the crosslinking was followed by measuring the gel content and by determination of the content o…
The current-voltage characteristics of Schottky diodes fabricated using as-grown diamond films depend on the electronegativities of metals. However for diamond films oxidized by boiling in a saturated solution of CrO in H2SO4 or by exposure to an oxygen plasma, this dependence vanishes. This is because of the adsorpti…
Grazing incidence x-ray diffraction has been used to characterize the near surface structure of an aromatic polyimide film. It is shown that within the first 90 \AA{} from the surface the ordering of the polymer molecules is markedly enhanced. As the penetration depth of the x rays decreases, reflections characteristi…