Spectroscopy of Solid-State Laser-Type Materials, 1987
Ettore Majorana International Science Series, Vol. 30

This book presents an account of the course "Spectroscopy of Solid-State Laser-Type Materials" held in Erice, Italy, from June 16 to 30, 1985. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Centre for Scientific Culture. The objective of the course was to present and examine the recent advances in spectroscopy and theoretical modelling relevant to the interpretation of luminescence and laser phenomena in several classes of solid-state materials. The available solid-state matrices (e.g. halides, oxides, glasses, semiconductors) and the full range of possible activators (transition ions, rare earth ions, post-transition ions, actinides, color centres) were considered. By bringing together specialists in the fields of solid-state luminescence and of solid-state laser materials, this course provided a much-needed forum for the critical . assessment of past developments in the R&D of solid-state lasers. Additional objectives of the meeting were to identify new classes of host/activator systems that show promise of laser operation; to alert researchers in solid-state luminescence to current technological needs for solid-state tunable lasers operating in the visible and infrared spectral regions; and generally to provide the scientific background for advanced work in solid state lasers. A total of 71 participants came from 54 laboratories and 21 nations (Austria, Belgium, Canada, F.R. of Germany, France, Greece, Ireland, Israel, Italy, the Netherlands, P.R. of China, Poland, Rumania, Sweden, Switzerland, South Korea, Spain, Turkey, United Kingdom, U.S.A. and U.S.S.R.).

Recent Trends in Laser Material Research.- Abstract.- I. Introduction and Historical Perspective.- I.A. Mental Connections, Mental Stumbling Blocks, and Serendipity.- II. Classification of Laser R&D By Analogy to Electronics.- II.A. Oscillators.- II.B. Amplifiers.- II. C. Drivers.- II.D. Frequency Converters.- II.E. Pulse-Forming Networks.- II. F. Systems.- II.G. Instrumentation.- III. Recent Advances in Laser Materials.- III.A. Gas Lasers.- III.B. Free-Electron Lasers.- III.C. Liquid Lasers.- III.D. Solid-State Materials.- 1. Nd3+ Lasers.- 2. Novel Cr3+ Lasers.- 3. TM Lasers.- 4. RE3+ -Activated Materials.- 5. Color-Center Lasers.- III.E. Solid-State Lasers for High-Power Applications.- 1. The ICF Program.- 2. LLNL Assessment of SSI Materials for High-Power Lasers.- III.F. Semiconductor Lasers and Drivers.- III.G. Modulation, Optical Switching and Gating:.- 1. Laser Diodes in Optical Communications.- 2. Optical Gates.- III.H. Frequency Conversion.- III.I. Pulse-Forming Networks and the Production of Femtosecond Pulses.- IV. Future Trends.- IV.A. Laser Devices and the Information Explosion.- IV.B. Laser for Energy Production and Energy Delivery.- IV.C. Laser “Metrology” in Science and Technology.- IV.D. Future Role of the SSI Materials.- IV. E. Exhortation.- References.- Spectroscopy of Ionic Solid-State Laser Materials.- Abstract.- I. Spontaneous Emission, Absorption and Induced Emission.- I.A. Classical Bound, Radiating Electron.- I.B. Quantum-Mechanical Radiative Decay.- I.C. Absorption and Induced Emission.- I.D. Absorption Coefficient and Absorption Cross Section.- I.E. Saturation.- I.F. Line Broadening.- I.G. Nonradiative Decay.- I.H. Degenerate Levels.- II. Spectroscopy of molecular Systems. Basic Concepts.- II.A. The Adiabatic Approximation.- 1. The Hamiltonian of a Molecular System.- 2. The Meaning of the Adiabatic Approximation.- II.B. Probability of Radiative Transitions.- II.C. The Franck-Condon Principle.- III. Spectroscopy of Impurity Ions in Solids.- III.A. Introduction.- III.B. Vibrations of Solids.- III.C. Generalization of the Franck-Condon Approximation.- III.D. Radiative Transitions.- 1. Radiated and Absorbed Power.- 2. Characteristics of the Entire Band.- 3. Radiative Transitions in the Presence of a Localized Vibration.- III.E. The Formula of Huang and Rhys.- IV. Radiationless Deactivation opf Impurity Ions in Solids.- IV.A. Deviations from the Adiabatic Approximation.- IV.B. Mechanism for Radiationless Transitions.- IV.C. Radiationless Transitions.- V. Laser Conditions.- V.A. Essential Features of a Laser System.- V.B. Three-Level Scheme.- V.C. Four-Level Scheme.- V.D. Three-Level Laser.- V.E. Four-Level Laser.- VI. Examples of Ionic Solid-State Lasers.- VI.A. The Ruby Laser.- VI.B. The YAG: Nd Laser.- VII. Problems.- VIII. Solutions.- Acknowledgments.- References.- Optical Spectroscopy of Color Center in Ionic Crystals.- Abstract.- I. Single Vacancy Center in Alkali Halides.- I.A. F+Center in the Alkali Halides.- I.B. Optical Absorption by F Center.- I.C. Excited States of the F-Center.- I.D. Uniaxial Stress, Stark and Zeeman Spectroscopy.- II. Vacancy Aggregate Center.- II.A. Optical Transitions of F2 Center.- II.B. Uniaxial Stress and Stark Effects for Orthorhombic Center.- III. F ACenter.- IV. Electron Excess Center in Oxides.- V. Tl° Center In The Alkali Halides.- VI. Colour Center Lasers.- VI.A. Vibronically Tuned Solid State Lasers.- VI.B. LRaasteer sE quations for Opticall1y Pumped Four-Level.- VI.C. FA and FB Center Lasers.- VI.D. F2 + Center Lasers.- VI.E. The Tl° Center Lasers.- VI.F. Ultra-short Pulses Using Colour Center Lasers.- References.- Electronic States of Transition Metal Ions in Solids.- Abstract.- I. Introduction.- II. Hamiltonian for a Transition Metal Ion in a Solid: Separation Of Electronic and Ionic Variables.- III. Transition Metal Ions in High Symmetry Crystal Fields.- IV. Transition Metal Ions in Tetrahedral Crystal Fields.- V. Low Symmetry Crystal Fields and Spin-Orbit Coupling.- References.- Radiative and Nonradiative Processes on Transition Metal Ions in Solids.- Abstract.- I. Introduction.- II. Radiative Transition Probabilities.- III. Effect of The Vibrating Lattice Environment on Optical Transitions.- IV. Vibronic Processes.- V. Nonradiative Processes on Transition Metal Ions.- References.- Transition Metal Ion-Doped Materials of Laser Interest.- Abstract.- I. Introduction.- II. Transition Metal Ion Systems.- II.A. Ti3+(3d)1.- II.B. V2+, Cr3+(3d)3.- II.C. Ni2+(3d)8.- II.D. Co2+(3d)7.- III. Concentration Quenching.- IV. Transition Metal Ion-Doped Glasses.- V. Chromium Doped Transparent Glass Ceramics.- References.- Progress in Rare-Earth and Actinide Spectroscopy.- Abstract.- I. Introduction.- II. Classical Spectroscopy of The Rare-Earth Ions.- III. Recent Progress in Rare-Earth Spectroscopy.- IV. Energy Transfer and Energy Migration.- IV.A. Theory of Energy Transfer.- 1. Two-site Nonresonant Process.- 2. One-site Raman Process.- 3. One-site Resonant Process.- 4. One-site Nonresonant Process.- IV.B. Practical Systems.- IV.C. Examples of One-Step Energy Transfer.- IV.D. Examples of Energy Migration.- V. Nonradiative Transitions.- VI. Actinides.- VI.A. Closed Shell Ions.- VI.B. Ions with 5fn Configuration.- VII. Applications.- Acknowledgement.- References.- Spectroscopy of Post-Transition Metal Ions.- Abstract.- I. Introduction.- II. The Optical Properties of The Alkali Halide Phosphors Doped By s2 Configuration Ions (OR T1+ - Like Phosphors).- II.A. The Energy Level Scheme from the s2 Configuration of the Post-Transition Metals.- II.B. The Absorption and Emission Properties.- II.C. Polarization Effect.- II.D. Hydrostatic Pressure Effect.- II.E. Magnetic Field Effect.- II.F. The Decay-Curves.- II.G. Two-Photon Absorption.- II.H. Interpretation.- III. The Optical Properties of The Alkali Halide Phosphors Doped By d10 Configuration Ions.- III.A. The energy Level Scheme from the d10 Configuration Ions.- III.B. Absorption and Emission Spectra of NaF(Cu+) Phosphors —.- III.C. The Fluorescence Decays Under Excitation in 1Eg Excited State.- III.D. The Two-Photon Spectra.- IV. The Bi3+ Luminescence.- V. Some Applications Of Post-Transition Metal Ions.- V.A. NaI(Tl+) and Bi4Ge3O12 (BGO) as Scintillators.- V.B. Post-Transition Metal Ions for Tunable Solid-State Lasers.- VI. Conclusion.- Appendices.- Appendix A: Three Level Schema Including One Ground State, One Metastable State and One Excited State.- Appendix B: Theory of Two-Photon Spectroscopy.- Appendix C: Jahn-Teller Effect (JTE) for an Octahedron Molecule AX6 -.- Acknowledgements.- References.- Advances in Semiconductor Spectroscopy.- Abstract.- I. Introduction.- II. Electron States in a Semiconductor.- III. Impurity States.- IV. Semiconductor Statistics and The Fermi Level In Thermal Equilibrium.- IV.A. Fermi Level Near the Middle of the Gap: the Non-Degenerate Case.- IV.B. Fermi Level Near the Band Edge: Degeneracy -.- IV.C. General Case: Fermi Level Pinning.- V. Non-Equilibrium Populations and Quasi-Equilibrium Distributions.- V.A. The Quasi-Fermi Level.- V.B. Carrier Injection.- VI. Excitons.- VII. Interaction of Carriers With Radiation.- VII.A. Absorption and Emission of Bandgap Light.- VII.B. Digression on the Chemical Potential.- VII.C. Condition for Lasing.- VIII. Quantum Wells and Superlattices.- IX. Conclusion.- Acknowledgments.- References.- Materials for Ionic Solid State Lasers.- Abstract.- I. Introduction.- II. Relevant Spectroscopic Parameters for Ionic Solid State Lasers.- II.A. Basic Laser Parameters.- 1. Laser Gain at Threshold.- 2. The Pump Energy and Power Necessary for Threshold.- 3. The Population Inversion.- 4. Optical Pumping to Reach Inversion.- 5. The Laser Output, Threshold and Differential Efficiency Versus Coupling.- 6. Oscillator Strengths and Hypersensitive Transitions.- 7. Nonradiative Transitions and Vibronics.- 8. Energy Transfer.- II. B. Merit Factor for Materials.- III. Material Engineering Approaches.- III.A. Material for C.W. Laser.- 1. The Powdered Samples Luminescence Method as an Approach to Merit Factor M (Global Optimization of M).- 2. Self-Quenching and Crystal Field Strength.- 3. Line Strength and Cross-Section (Optimization of t OOOP).- III.B. The High Power Laser Case.- 1. Thermal Properties for High Average Power Lasers.- 2. Optical Properties for High Peak Power Lasers.- III.C. Tunable Lasers.- 1. Role of Crystal Field.- 2. Role of Reabsorption.- III.D. Parameters for Typical Laser Materials.- IV. Conclusion.- References.- Glass Lasers and Solar Applications.- Abstract.- I. Introduction.- I.A. Glass Lasers.- I.B. Luminescent Solar Concentrators.- II. Requirements for Glass Lasers and Luminescent Solar Concentrators. Similarities and Differences.- II.A. Basic Parameters of a Laser.- III. Rare Earth Doped Laser Glasses.- III.A. Radiative Transition Probabilities and Laser Cross-Sections of Rare Earth Ions in Glasses.- III.B. Nonradiative Transitions.- 1. Multiphonon Relaxation in Lanthanide Ions.- 2. Cross-relaxations.- 3. Energy Transfer Between Ions in Glasses.- IV. Increase of Pumping Efficiencies by Radiative Trapping.- V. Luminescent Solar Concentrators (LSC).- V.A. Parameters Determining the Optical Plate Efficiency.- V.B. Rare Earth Ions in LSC.- V.C. Chromium Doped Materials for LSC.- 1. Nonradiative Relaxation of Cr (III) in Glasses.- 2. Chromium Doped Transparent Glass Ceramics-.- VI. Organic Dyes in Glasses as Possible Materials for Lasers and Solar Devices.- Acknowledgements.- References.- Recent Development in Phosphor Materials.- Abstract.- I. Introduction and Overview Of Phosphor Applications.- I.A. Connection Between Phosphor R&D and Laser- Material Research.- I.B. Overview of Phosphor Applications.- I.C. Status of Phosphor R&D.- 1. Phosphors for CRT Displays.- 2. Electroluminescent Phosphors.- 3. X-Ray Phosphors.- 4. Scintillators.- 5. Triboluminescent Phosphors.- 6. Infrared-to-Visible Conversion.- II. Phosphors For Fluorescent Lighting.- II.A. Rationale and Background Notes.- II.B. Methodology for the Development of New Phosphors.- II.C. Phosphor Synthesis and Characterization.- II.D. Mechanisms of Phosphor Operation.- II.E. Sensitization.- II.F. Tricolor Lamps.- II.G. Phosphor Problems in Lamp Fabrication.- III. Some Important Lighting Phosphors.- III.A. Halophosphate Phosphors.- III.B. Sn-Activated Sr Orthophosphate.- III.C. “Yellow Halo” and the Sensitization of Mn2+ in Apatites.- III.D. The Tricolor-Lamp Phosphors.- 1. BaMg2Al16O27: Eu.- 2. (Ce,Tb)MgAl11O19.- 3. Y2O3:EU.- III.E. UV - Emitting Phosphors.- IV. Novel Borate Phosphors.- V. Two-Visible-Photon Conversion Of A UV Photon.- VI. Concluding Remarks.- References.- Long Seminars: High Pressure Properties of Some Laser Materials.- Abstract.- I. Introduction.- II. “Ruby-Type” Laser Materials.- II.A. Ruby.- II.B. Alexandrite.- II.C. Emerald.- III. The 02 Molecule In Alkali-Halides.- IV. Semiconductors.- IV.A. Absorption Spectrum of n Type Samples of GaAs:Cr+.- IV.B. Emission Spectra from Level 5E of Cr2+ in GaAs.- V. Pressure Shifts in the Gaps of Some Semiconductors.- V.A. Direct versus Indirect Gap in GaAs.- V.B. Band Gap Variations in Some Widely Used Semiconductors.- References.- Laser-Induced Dynamic Gratings and Four Wave Mixing-Material Investigations and Coherent Light Amplification.- Abstract.- I. Permanent And Dynamic Grating.- II. Two-Beam Interference.- III. Types of gratings. Material response.- IV. Optical Amplitude and Phase Gratings.- V. Diffraction at Optical Gratings.- VI. Experimental Geometries for Grating Production and Detection.- VII. Forced Light-Scattering.- VIII. Transient Grating in The Framework Of Nonlinear Optics.- IX. Investigation of Carrier Dynamics in Semiconductors.- X. Excitation Energy Diffusion in Solids.- XI. Coherent Light Amplification.- XII. Conclusion and Outlook.- Acknowledgements.- References.- Beta? Alumina: a Solid Electrolyte as a Solid State Laser Host.- Abstract.- I. Introduction.- II. Material Synthesis.- III. Structure of Nd3+ Beta? Alumina.- IV. Optical Properties of Na+ - Nd3+ Beta? Aluminas.- V. Conclusions.- Acknowledgements.- References.- Photoacoustic and Photothermal Characterization of Laser Material.- Abstract.- I. Generation and Detection of Photothermal and Photoacoustic Signals.- II. Application to Spectroscopy. Opaque and Highly Transparent Samples.- III. Quantum Yield Determination.- IV. Transport Properties.- V. Nondestructive Evaluation. Photothermal Imaging.- VI. Conclusion.- References.- Laser Processes in Semiconductors.- Abstract.- I. Introduction.- II. Pump Sources for Semiconductor Lasers.- III. Intrinsic Laser Processes.- IV. Extrinsic Laser Processes.- V. Parametric Laser Processes.- Acknowledgements.- References.- Spectroscopy Using Lasers.- Abstract.- I. Introduction.- I.A. Laser Properties and Historical Prospective.- I.B. Optical Spectroscopies of Solids.- II. Laser Spectroscopy of Solids.- II.A. Introduction.- II.B. Experimental Methodologies.- 1. Static Spectroscopy.- 2. Dynamic Spectroscopy.- III. Concluding Remarks.- Acknowledgements.- References.- Excited State Absorption of Cr3+ in Low Ligand Field Hosts.- Abstract.- I. Introduction.- II. The a1g, Coupling Model.- III. Excited State Absorption Measurements.- III.A. Experimental.- III.B. ESA Difference Spectra GSGG:Cr and GSAG:Cr.- III.C. ESA Difference Spectrum of Cr3+ in K2NaScF6:Cr3+.- IV. Excited State Absorption Cross Sections.- V. Conclusion.- Acknowledgements.- References.- Quantum Well Structures for Optical Signal Processing.- Abstract.- I. Introduction.- II. Optical Nonlinearities Of Multiple Quantum Well Structures.- III. Electro-Absorption in GaAs/AlGaAs Multiple Quantum Well Structures.- IV. Conclusion.- Acknowledgements.- References.- Electronic Raman Spectroscopy (Abstract Only).- Localization of Excitons in Weakly Disordered Systems (Abstract Only).- Deep Impurity Levels in Semiconductors. Current State of our Understanding(Abstract Only).- Achievements in the Field of Physics and Spectroscopy of Activated Laser Crystals (Abstract Only).- The Oxidation States of Ti in Sapphire Crystals (Abstract Only).- Short Seminars (Abstracts): Laser Spectroscopy of Some Yag: R-E Systems.- Structure and Luminescence Properties of U6+ Centers in Alkali and Alkaline Earth Fluorides.- Spectroscopy of KZnF3:Co.- Two Photon Excitation Spectroscopy of Actinyl`ions.- Relaxation Rates for Ho+3in Tellurite and Fluoride Glasses.- Energy Migration in a One-Dimensional System.- Intraion Spectral Interference Elimination in EUP5O14 by Time Resolved Spectroscopy and New Excitation Transfer Experiments in Tb0.66Eu0.33P5O14 Crystals.- Intermolecular Interactions and Luminescence Spectroscopy of Twodimensional Layered Solids.- Energy Transfer in Li6Gd(BO3)3.- 5D3-5D4 Cross-Relaxation of Tb3+Pairs in CsCdBr3 Crystals.- Energy Migration and Energy Transfer in GdB3O6:Bi,Tb.- On the Dielectric Constants in Donor-Acceptor Pair Luminescence.- Optical Feedback Stabilization of a Semiconductor Laser.- Temperature Dependence of the Fluorescence Lineshape and Lifetime of Titanium-Doped Sapphire.- Energy Transfer in Li(Gd,Y)0.98Ce0.01Tb0.01 F4.- Laser Oscillation in LiNbO3Nd,MgO.- Effects of Electron Bombardment on CdSe Crystals at T?4K.- Two Photon Absorption in Lanthanide Ions in Crystals.- Single Mode Neodymium Fibre Laser.- Summary of the Meeting.- Participants.