Inorganic Glasses for Photonics

Animesh Jha is Professor of Applied Materials Science at the University of Leeds. He is a fellow of the Society of Glass Technology whose research areas include photonic materials, fiber and planar light waveguide devices, spectroscopy of rare-earth and transition metal ions, raman spectroscopy of glass and ceramic materials, minerals and mineralogy.

"The target audience for this text is graduate students and researchers in functionalizing properties for photonic applications. Anyone concerned with the structure-property relationship of materials, however, will profit from reading this book" The Oprical Society, July 2017

• Series Preface xiiiPreface xv1. Introduction 11.1 Definition of Glassy States 11.2 The Glassy State and Glass Transition Temperature (Tg) 11.3 Kauzmann Paradox and Negative Change in Entropy 41.4 Glass-Forming Characteristics and Thermodynamic Properties 51.5 Glass Formation and Co-ordination Number of Cations 141.6 Ionicity of Bonds of Oxide Constituents in Glass-Forming Systems 201.7 Definitions of Glass Network Formers, Intermediates and Modifiers and Glass-Forming Systems 231.7.1 Constituents of Inorganic Glass-Forming Systems 241.7.2 Strongly Covalent Inorganic Glass-Forming Networks 261.7.3 Conditional Glass Formers Based on Heavy-Metal Oxide Glasses 291.7.4 Fluoride and Halide Network Forming and Conditional Glass-Forming Systems 311.7.5 Silicon Oxynitride Conditional Glass-Forming Systems 361.7.6 Chalcogenide Glass-Forming Systems 371.7.7 Chalcohalide Glasses 451.8 Conclusions 46Selected Biography 46References 462. Glass Structure, Properties and Characterization 512.1 Introduction 512.1.1 Kinetic Theory of Glass Formation and Prediction of Critical Cooling Rates 512.1.2 Classical Nucleation Theory 522.1.3 Non-Steady State Nucleation 542.1.4 Heterogeneous Nucleation 552.1.5 Nucleation Studies in Fluoride Glasses 562.1.6 Growth Rate 582.1.7 Combined Growth and Nucleation Rates, Phase Transformation and Critical Cooling Rate 592.2 Thermal Characterization using Differential Scanning Calorimetry (DSC) and Differential Thermal Analysis (DTA) Techniques 622.2.1 General Features of a Thermal Characterization 622.2.2 Methods of Characterization 632.2.3 Determining the Characteristic Temperatures 642.2.4 Determination of Apparent Activation Energy of Devitrification 662.3 Coefficients of Thermal Expansion of Inorganic Glasses 682.4 Viscosity Behaviour in the near-Tg, above Tg and in the Liquidus Temperature Ranges 712.5 Density of Inorganic Glasses 752.6 Specific Heat and its Temperature Dependence in the Glassy State 762.7 Conclusion 77References 773. Bulk Glass Fabrication and Properties 793.1 Introduction 793.2 Fabrication Steps for Bulk Glasses 803.2.1 Chemical Vapour Technique for Oxide Glasses 803.2.2 Batch Preparation for Melting Glasses 813.2.3 Chemical Treatment Before and During Melting 813.3 Chemical Purification Methods for Heavier Oxide (GeO2 and TeO2) Glasses 843.4 Drying, Fusion and Melting Techniques for Fluoride Glasses 873.4.1 Raw Materials 883.4.2 Control of Hydroxyl Ions during Drying and Melting of Fluorides 883.5 Chemistry of Purification and Melting Reactions for Chalcogenide Materials 913.6 Need for Annealing Glass after Casting 963.7 Fabrication of Transparent Glass Ceramics 973.8 Sol–Gel Technique for Glass Formation 993.8.1 Background Theory 993.8.2 Examples of Materials Chemistry and Sol–Gel Forming Techniques 1033.9 Conclusions 105References 1054. Optical Fibre Design, Engineering, Fabrication and Characterization 1094.1 Introduction to Geometrical Optics of Fibres: Geometrical Optics of Fibres and Waveguides (Propagation, Critical and Acceptance Angles, Numerical Aperture) 1094.2 Solutions for Dielectric Waveguides using Maxwell’s Equation 1144.2.1 Analysis of Mode Field Diameter in Single Mode Fibres 1154.3 Materials Properties Affecting Degradation of Signal in Optical Waveguides 1174.3.1 Total Intrinsic Loss 1174.3.2 Electronic Absorption 1184.3.3 Experimental Aspects of Determining the Short Wavelength Absorption 1214.3.4 Scattering 1214.3.5 Infrared Absorption 1244.3.6 Characterization of Vibrational Structures using Raman and IR Spectroscopy 1264.3.7 Experimental Aspects of Raman Spectroscopic Technique 1274.3.8 Fourier Transform Infrared (FTIR) spectroscopy 1284.3.9 Examples of the Analysis of Raman and IR spectra 1304.4 Fabrication of Core–Clad Structures of Glass Preforms and Fibres and their Properties 1414.4.1 Comparison of Fabrication Techniques for Silica Optical Fibres with Non-silica Optical Fibres 1434.4.2 Fibre Fabrication using Non-silica Glass Core–Clad Structures 1514.4.3 Loss Characterization of Fibres 1534.5 Refractive Indices and Dispersion Characteristics of Inorganic Glasses 1584.5.1 Experimental Procedure for Measuring Refractive Index of a Glass or Thin Film 1634.5.2 Dependence of Density on Temperature and Relationship with Refractive Index 1664.5.3 Effect of Residual Stress on Refractive Index of a Medium and its Effect 1694.6 Conclusion 170References 1705. Thin-film Fabrication and Characterization 1785.1 Introduction 1785.2 Physical Techniques for Thick and Thin Film Deposition 1795.3 Evaporation 1795.3.1 General Description 1795.3.2 Technique, Materials and Process Control 1795.4 Sputtering 1815.4.1 Principle of Sputtering 1815.5 Pulsed Laser Deposition 1835.5.1 Introduction and Principle 1835.5.2 Process 1845.5.3 Key Features of PLD process 1865.5.4 Controlling Parameters and Materials Investigated 1875.5.5 Fabrication of Thin Film Structures using PLD and Molecular Beam Epitaxy 1885.6 Ion Implantation 1925.6.1 Introduction 1925.6.2 Technique and Structural Changes 1925.6.3 Governing Parameters for Ion Implantation 1935.6.4 Materials Systems Investigated 1945.7 Chemical Techniques 1945.7.1 Characteristics of Chemical Vapour Deposition Processes 1955.7.2 Materials System Studied and Applications 1965.7.3 Molecular Beam Epitaxy (MBE) 1965.8 Ion-Exchange Technique 1975.9 Chemical Solution or Sol–Gel Deposition (CSD) 2005.9.1 Introduction 2005.9.2 CSD Technique and Materials Deposited 2025.10 Conclusion 203References 2036. Spectroscopic Properties of Lanthanide (Ln3+) and Transition Metal (M3+)-Ion Doped Glasses 2096.1 Introduction 2096.2 Theory of Radiative Transition 2096.3 Classical Model for Dipoles and Decay Process 2126.4 Factors Influencing the Line Shape Broadening of Optical Transitions 2146.5 Characteristics of Dipole and Multi-Poles and Selection Rules for Optical Transitions: 2186.5.1 Analysis of Dipole Transitions Based on Fermi’s Golden Rule 2196.5.2 Electronic Structure and Some Important Properties of Lanthanides 2216.5.3 Laporte Selection Rules for Rare-Earth and Transition Metal Ions 2246.6 Comparison of Oscillator Strength Parameters, Optical Transition Probabilities and Overall Lifetimes of Excited States 2276.6.1 Radiative and Non-Radiative Rate Equation 2316.6.2 Energy Transfer and Related Non-Radiative Processes 2336.6.3 Upconversion Process 2376.7 Selected Examples of Spectroscopic Processes in Rare-Earth Ion Doped Glasses 2386.7.1 Spectroscopic Properties of Trivalent Lanthanide (Ln3+)-Doped Inorganic Glasses 2396.7.2 Brief Comparison of Spectroscopic Properties of Er3+-Doped Glasses 2416.7.3 Spectroscopic Properties of Tm3+-Doped Inorganic Glasses 2476.8 Conclusions 257References 2577. Applications of Inorganic Photonic Glasses 2617.1 Introduction 2617.2 Dispersion in Optical Fibres and its Control and Management 2617.2.1 Intramodal Dispersion 2627.2.2 Intermodal Distortion 2657.2.3 Polarization Mode Dispersion (PMD) 2667.2.4 Methods of Controlling and Managing Dispersion in Fibres 2677.3 Unconventional Fibre Structures 2697.3.1 Fibres with Periodic Defects and Bandgap 2697.3.2 TIR and Endlessly Single Mode Propagation in PCF with Positive Core–Cladding Difference 2727.3.3 Negative Core–Cladding Refractive Index Difference 2727.3.4 Control of Group Velocity Dispersion (GVD) 2737.3.5 Birefringence in Microstructured Optical Fibres 2747.4 Optical Nonlinearity in Glasses, Glass-Ceramics and Optical Fibres 2757.4.1 Theory of Harmonic Generation 2757.4.2 Nonlinear Materials for Harmonic Generations and Parametric Processes 2797.4.3 Fibre Based Kerr Media and its Application 2857.4.4 Resonant Nonlinearity in Doped Glassy Hosts 2877.4.5 Second Harmonic Generation in Inorganic Glasses 2887.4.6 Electric-Field Poling and Poled Glass 2897.4.7 Raman Gain Medium 2917.4.8 Photo-induced Bragg and Long-Period Gratings in Fibres 2927.5 Applications of Selected Rare-earth ion and Bi-ion Doped Amplifying Devices 2947.5.1 Introduction 2947.5.2 Examples of Three-Level or Pseudo-Three-Level Transitions 2967.5.3 Examples of Four-Level Laser Systems 3007.6 Emerging Opportunities for the Future 3027.7 Conclusions 303References 304Supplementary References 311Symbols and Notations Used 315Index 317