CRYSTALLINE MATERIALS Introduction Physical Properties Optical Properties Mechanical Properties Thermal Properties Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties GLASSES Introduction Commercial Optical Glasses Specialty Optical Glasses Fused Silica Fluoride Glasses Chalcogenide Glasses Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties Special Glasses POLYMERIC MATERIALS Optical Plastics Index of Refraction Nonlinear Optical Properties Thermal Properties Engineering Data METALS Physical Properties of Selected Metals Optical Properties Mechanical Properties Thermal Properties Mirror Substrate Materials LIQUIDS Introduction Water Physical Properties of Selected Liquids Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Commercial Optical Liquids GASES Introduction Physical Properties of Selected Gases Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Atomic Resonance Filters APPENDICES Safe Handling of Optical Materials Abbreviations, Acronyms, and Mineralogical or Common Names for Optical Materials Abbreviations for Methods of Preparing Optical Materials and Thin Films Fundamental Physical Constants Units and Conversion Factors

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Handbook of Optical Materials

Optical second harmonic generation in piezoelectric crystals

Integrated optics and new wave phenomena in optical waveguides

Germania glass was prepared from high purity GeO2 powder. Refractive-index dispersion was used to calculate material dispersion and to provide a model for representing the dispersion of GeO2–SiO2 glasses. The wavelength of zero material dispersion is found to be in agreement with theoretical calculations. Modal propagation is modeled for a GeO2 core–silica clad fiber. Results support compositional dependence of profile dispersion in GeO2–SiO2 fibers.

Dispersion in GeO2-SiO2 glasses.

High-voltage Al/sub 0.22/Ga/sub 0.78/N-GaN high-electron mobility transistors have been fabricated using multiple field plates over dielectric passivation layers. The device breakdown voltage was found to increase with the addition of the field plates. With two field plates, the device showed a breakdown voltage as high as 900 V. This technique is easy to apply, based on the standard planar transistor fabrication, and especially attractive for the power switching applications.

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High breakdown voltage AlGaN-GaN HEMTs achieved by multiple field plates

Electro‐optic properties of some abo3 perovskites in the paraelectric phase

The onset of gate-drain avalanche imposes an important fundamental constraint on the drain voltage swing, and hence, on the output power of GaAs FET's. In this paper we show that recognition of the role of surface depletion and proper attention to channel design can yield avalanche voltage factors of 2-3 above bulk values. The appropriate design strategy is minimization of the undepleted epitaxial charge per unit area (Q u ) between gate and drain, which, in turn, dictates a gate-notch depth approximately equal to the surface zero-bias depletion depth. A simple lateral spreading model is proposed which predicts that V_{L} \sim 50Q\min{u}\max{-1} , where V L is the gate-drain avalanche voltage and Q u is measured in units of 1012electrons/cm2. This prediction is supported by a large body of experimental dc and pulse data, although considerable scatter is observed which we have attributed to epi charge nonuniformities, premature avalanche at the rough edges of AI gates formed by a liftoff process, and surface charging variations associated with dielectric passivation. The observed dependence of V L on epi charge rather than on doping level, as predicted for bulk avalanche, provides convincing evidence for nonbulk two-dimensional avalanche in the thin-film ( Q_{u} ) FET geometry. In thick films ( Q_{u} > 2.6 ), on the other hand, it is found that the bulk avalanche predictions are reasonably accurate. In terms of saturated epi current I s , the bulk regime corresponds to I_{s} > 450 mA/mm and the lateral spreading (thin-film) regime to I_{s} mA/mm. Finally, we have found that gate-drain avalanche is the major cause of output saturation as a function of drain potential in power GaAs FET's.

Control of gate&#8212;Drain avalanche in GaAs MESFET's

Zinc chloride glass is a potentially useful medium for ultralow‐loss (∼1 dB/103 km) optical fibers for wavelengths in the 3.5–4‐μm region. In this region, intrinsic absorption, scatter, and material dispersion are all expected to be small, and the common fully oxidized transition metal impurities and H2O should exhibit extremely weak absorption as well.

ZnCl2 glass: A potential ultralow‐loss optical fiber material

Catastrophic source-drain burnout is an important failure mode in GaAs power FET's. In this paper we show that short-term (instantaneous) and long-term (aging) failures have different physical origins provided the underlying drain ohmic-contact weakness has been suppressed by use of a recessed n+drain ledge geometry. With this drain configuration, instantaneous burnout is due to thermal runaway of the buffer/substrate when local temperatures reach the 500-550°C range. For our typical devices With 30-50-µm-thick substrates, the associated de burnout power is 4-5 W/mm of gate periphery. Long-term aging failure, on the other hand, results from chemical changes at the GaAs surface between gate and drain. These changes induce localized areas of avalanche white-light emission, particularly along the n+ledge, which serve as burnout precursors. A series of aging, surface etching, and passivation experiments has revealed that oxygen probably plays a major role in the aging process, perhaps through its known effect on free arsenic formation. Moreover, it is found that minimization of the oxygen content at the top surface by using si 3 N 4 :H passivation rather than SiO 2 not only prevents white-light emission but increases the median life at 310°C channel temperature from 2.5 to more than 500 h.

Long-term and instantaneous burnout in GaAs power FET's: Mechanisms and solutions

A recent investigation of the binary borosilicate glass system has led to the realization of a useful cladding material for pure fused silica core fiber optical waveguides. The feature which makes the borosilicate glass useful is that its index of refraction is sufficiently less than that of pure fused silica to allow light guidance in silica core‐borosilicate clad fibers. The previous work offered no explanation for the observed but unexpected behavior of the borosilicate refractive index. Continued studies of this glass system have now led to a quantative explanation of the refractive index behavior. Two theoretical approaches are discussed. One is based on the Sellmeier dispersion model and the other on a molar refractivity analysis. The main quantities of interest turn out to be density, composition, structure, and ionicity. An important prediction based on this work is that properly quenched borosilicate glass can have a refractive index even lower than previously observed. This prediction was subseq...

S.H. Wemple

Papers

Electro‐optic properties of some abo3 perovskites in the paraelectric phase

Control of gate—Drain avalanche in GaAs MESFET's

ZnCl2 glass: A potential ultralow‐loss optical fiber material

Long-term and instantaneous burnout in GaAs power FET's: Mechanisms and solutions

Binary SiO2–B2O3 glass system: Refractive index behavior and energy gap considerations

S.H. Wemple

Papers

Electro‐optic properties of some abo3 perovskites in the paraelectric phase

Control of gate&#8212;Drain avalanche in GaAs MESFET's

ZnCl2 glass: A potential ultralow‐loss optical fiber material

Long-term and instantaneous burnout in GaAs power FET's: Mechanisms and solutions

Binary SiO2–B2O3 glass system: Refractive index behavior and energy gap considerations

Control of gate—Drain avalanche in GaAs MESFET's