Optical Properties of Highly Transparent Solids

Optical Properties of Highly Transparent Solids

Author: Bernard Bendow

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 525

ISBN-13: 1468421786

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Although much work has been performed on measure ments and interpretation of light absorption by opaque or nearly opaque solids, it is surprising to note that until recently relatively little reliable experimental data, and much less theoretical work was available on the nature of transparent solids. This, in spite of the fact that a vast majority of engineering and device ap plications of a solid depend on its optical transparency. Needless to say, all solids are both transparent and opa que depending on the spectral region of consideration. The absorption processes that limit the transparency of a solid are either due to lattice vibrations, as in ionic or partially ionic solids, or due to electronic transi tions, both intrinsic and impurity-induced. For most materials, a sufficiently wide spectral window exists be tween these two limits, where the material is transpar ent. In general, the absorption coefficient, in the long wavelength side of, but sufficiently away from, the fun damental absorption edge, is relatively structureless and has an exponential dependence on frequency. Recent evi dence suggests that in the short wavelength side of the one-phonon region, but beyond two- or three-phonon sin gularities, the absorption coefficient of both polar and nonpolar solids is also relatively structureless and de pends exponentially on frequency.


Infrared Properties of Highly Transparent Solids

Infrared Properties of Highly Transparent Solids

Author: Morris Braunstein

Publisher:

Published: 1980

Total Pages: 8

ISBN-13:

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The optical properties of highly transparent single crystals of KBr, KCl, CaF2 and BaF2 have been measured using laser calorimetric techniques and wavelength modulation spectroscopy techniques in the spectral range for 2.5 to 12 microns in cooperation with the University of California at Los Angeles (UCLA). Rich and varied absorption structures in the spectra were observed in all of the crystals enabling an identification of volume and surface absorption. Similar dominant bands are observed in many of the crystals indicating the presence of common impurities regardless of the crystal and origin of its growth. However, varied fine structure was observed in different crystals which are indicative of the individual characteristics of the chemistry of the crystal preparation. The measurements were performed in laboratory and dry nitrogen ambients and the physical absorption and desorption of surface contaminants was readily observed. Ellipsometric techniques were developed to evaluate and measure the strain and anisotropy in infrared optical films. Improved Reactive Atmosphere Processing, (RAP), techniques were developed and studied using a two zone RAP furnace for single crystal growth of BaF2 and CaF2 which resulted in improved infrared transmission in the 3 to 5 micron wavelength region for the first time.


Far-Infrared Properties of Solids

Far-Infrared Properties of Solids

Author: S. Mitra

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 613

ISBN-13: 1468418637

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This book provides an account of modern aspects relating far infrared radiation to properties of solids; it encompasses both theoretical and experimental considerations. Written at the gradu ate level, it attempts a threefold purpose; an indication of the breadth of the subject, an in-depth examination of important areas, and reference material to complement a text for a course. The treatment and organization of material here is compatible with a preceding volume of this series on "Optical Properties of Solids." Chapters 1-6 present material concerned principally with experimental considerations necessary to the carrying out of meas urements in the far infrared spectral region. They also serve to provide considerable introductory material for the remaining chap ters which deal with various areas that offer theoretical treat ments utilizing and understanding far infrared properties of solids. Several lectures presented at the Institute could not be in cluded in this book for two reasons: (i) Final versions of the lecture notes suitable for publication never arrived from several lecturers; (ii) Some materials were deliberately left out fro~ this book as they were also presented at an earlier NATO Institute and form part of a preceding volume edited by us in this series. In particular, it is recommended that Chapters 14 and 15, viz., in frared and Raman spectra due to lattice vibrations by S. S. Mitra and impurity induced lattice absorption by L. Genzel in "Optical Properties of Solids'· be read concurrently with the present volume.


Characterization of Infrared Optical Properties of Transparent Materials

Characterization of Infrared Optical Properties of Transparent Materials

Author: Rubin Braunstein

Publisher:

Published: 1983

Total Pages: 28

ISBN-13:

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Chemical and structural imperfections which occur in highly transparent insulators and semiconductors were studied by a range of electromagnetic and electronic techniques. These utilized infrared wavelength modulation, high contrast Raman and Brillouin scattering and photoinduced transients spectroscopy techniques. The spectoral distribution of the absorption in the spectral region from 2.5-12 gamma was measured by infrared wavelength modulation techniques on: CaF2, LiF, NaCl, NaF, LaF3, BaF2, MgF2, SrF2, MgO, KCl, and KBr. (Author).