Page 8 - Chalcogenide Glasses for Infrared Optics

Contents

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
1 Transmission of Light by Solids . . . . . . . . . . . . . . . . 1
1.1 Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Beginning of Transmission of Light—
An Electronic Transition . . . . . . . . . . . . . . . . 2
1.3 Long-Wavelength Cutoff . . . . . . . . . . . . . . . . 5
1.4 Extrinsic Loss within the Band, Impurities,
Scatter, and Quality . . . . . . . . . . . . . . . . . . . . . 10
1.5 Optical Constants and Dispersion
due to Strong Absorption . . . . . . . . . . . . . . . . 12
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2 Chalcogenide Glasses . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1 Historical Development . . . . . . . . . . . . . . . . . 17
2.2 The Periodic Table and Glass Formation . . . 21
2.3 Evaluating Possible Glass Forming Systems . . . 29
2.4 Qualitative Evaluation of Compositions
for Development . . . . . . . . . . . . . . . . . . . . . . . 35
2.5 General Physical Properties of
Chalcogenide Glasses . . . . . . . . . . . . . . . . . . . 40
2.5.1 Softening Points and Hardness . . . . 40

2.5.2 Thermal Coefficients of Expansion . . . 41
2.5.3 Density . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.5.4 Molar Refraction . . . . . . . . . . . . . . . . . 42
2.5.5 Electrical Properties . . . . . . . . . . . . . . 47
2.5.6 Physical Strength . . . . . . . . . . . . . . . . . 47
2.5.7 Softening Points . . . . . . . . . . . . . . . . . . 48
2.6 Chemical Bonding in Chalcogenide Glasses . . . 48
2.6.1 Composition Location in the
Glass Forming Diagram . . . . . . . . . . . 48
2.6.2 Molecular Vibrations of Constituent
Atoms . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.6.3 Mass Spectrometric Investigation
of Bonding in the Glasses . . . . . . . . . 55
2.6.4 X-ray Radial Distribution Analysis of
Chalcogenide Glasses . . . . . . . . . . . . 57
2.6.5 Conclusions from the TI Exploratory
Programs of 1962 to 1965 . . . . . . . . . 59

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