Ruby laser

About: Ruby laser is a research topic. Over the lifetime, 2474 publications have been published within this topic receiving 38933 citations. The topic is also known as: corundum laser & ruby rod.

Principles of Lasers

Abstract: 1 Introductory Concepts.- 1.1 Spontaneous and Stimulated Emission, Absorption.- 1.1.1 Spontaneous Emission.- 1.1.2 Stimulated Emission.- 1.1.3 Absorption.- 1.2 The Laser Idea.- 1.3 Pumping Schemes.- 1.4 Properties of Laser Beams.- 1.4.1 Monochromaticity.- 1.4.2 Coherence.- 1.4.3 Directionality.- 1.4.4 Brightness.- Problems.- 2 Interaction of Radiation with Matter.- 2.1 Summary of Blackbody Radiation Theory.- 2.2 Absorption and Stimulated Emission.- 2.2.1 Rates of Absorption and Stimulated Emission.- 2.2.2 Allowed and Forbidden Transitions.- 2.2.3 Transition Cross Section, Absorption and Gain Coefficient.- 2.3 Spontaneous Emission.- 2.3.1 Semiclassical Approach.- 2.3.2 Quantum Electrodynamic Approach.- 2.3.3 Einstein Thermodynamic Treatment.- 2.3.4 Radiation Trapping, Superradiance, Superfluorescence, and Amplified Spontaneous Emission.- 2.4 Nonradiative Decay.- 2.5 Line Broadening Mechanisms.- 2.5.1 Homogeneous Broadening.- 2.5.2 Inhomogeneous Broadening.- 2.5.3 Combined Effect of Line Broadening Mechanisms.- 2.6 Saturation.- 2.6.1 Saturation of Absorption: Homogeneous Line.- 2.6.2 Gain Saturation: Homogeneous Line.- 2.6.3 Inhomogeneously Broadened Line.- 2.7 Degenerate Levels.- 2.8 Relation between Cross Section and Spontaneous Radiative Lifetime.- 2.9 Molecular Systems.- 2.9.1 Energy Levels of a Molecule.- 2.9.2 Level Occupation at Thermal Equilibrium.- 2.9.3 Radiative and Nonradiative Transitions.- Problems.- References.- 3 Pumping Processes.- 3.1 Introduction.- 3.2 Optical Pumping.- 3.2.1 Pumping Efficiency.- 3.2.2 Pump Light Distribution.- 3.2.3 Pumping Rate.- 3.3 Electrical Pumping.- 3.3.1 Electron Impact Excitation.- 3.3.2 Spatial Distribution of the Pump Rate.- 3.3.3 Pumping Efficiency.- 3.3.4 Excitation by (Near) Resonant Energy Transfer.- Problems.- References.- 4 Passive Optical Resonators.- 4.1 Introduction.- 4.2 Plane-Parallel Resonator.- 4.2.1 Approximate Treatment of Schawlow and Townes.- 4.2.2 Fox and Li Treatment.- 4.3 Confocal Resonator.- 4.4 Generalized Spherical Resonator.- 4.4.1 Mode Amplitudes, Diffraction Losses, and Resonance Frequencies.- 4.4.2 Stability Condition.- 4.5 Unstable Resonators.- Problems.- References.- 5 Continuous Wave and Transient Laser Behavior.- 5.1 Introduction.- 5.2 Rate Equations.- 5.2.1 Four-Level Laser.- 5.2.2 Three-Level Laser.- 5.3 CW Laser Behavior.- 5.3.1 Four-Level Laser.- 5.3.2 Three-Level Laser.- 5.3.3 Optimum Output Coupling.- 5.3.4 Reasons for Multimode Oscillation.- 5.3.5 Single-Line and Single-Mode Oscillation.- 5.3.6 Two Numerical Examples.- 5.3.7 Frequency Pulling and Limit to Monochromaticity.- 5.3.8 Lamb Dip and Active Stabilization of Laser Frequency.- 5.4 Transient Laser Behavior.- 5.4.1 Spiking Behavior of Single-Mode and Multimode Lasers.- 5.4.2 Q-Switching.- 5.4.2.1 Methods of Q-Switching.- 5.4.2.2 Operating Regimes.- 5.4.2.3 Theory of Q-Switching.- 5.4.2.4 A Numerical Example.- 5.4.3 Mode Locking.- 5.4.3.1 Methods of Mode Locking.- 5.4.3.2 Operating Regimes.- 5 5 Limits to the Rate Equations.- Problems.- References.- 6 Types of Lasers.- 6.1 Introduction.- 6.2 Solid-State Lasers.- 6.2.1 The Ruby Laser.- 6.2.2 Neodymium Lasers.- 6.3 Gas Lasers.- 6.3.1 Neutral Atom Lasers.- 6.3.2 Ion Lasers.- 6.3.2.1 Ion Gas Lasers.- 6.3.2.2 Metal Vapor Lasers.- 6.3.3 Molecular Gas Lasers.- 6.3.3.1 Vibrational-Rotational Lasers.- 6.3.3.2 Vibronic Lasers.- 6.3.3.3 Excimer Lasers.- 6.4 Liquid Lasers (Dye Lasers).- 6.4.1 Photophysical Properties of Organic Dyes.- 6.4.2 Characteristics of Dye Lasers.- 6.5 Chemical Lasers.- 6.6 Semiconductor Lasers.- 6.6.1 Photophysical Properties of Semiconductor Lasers.- 6.6.2 Characteristics of Semiconductor Lasers.- 6.7 Color-Center Lasers.- 6.8 The Free-Electron Laser.- 6.9 Summary of Performance Data.- Problems.- References.- 7 Properties of Laser Beams.- 7.1 Introduction.- 7.2 Monochromaticity.- 7.3 First-Order Coherence.- 7.3.1 Complex Representation of Polychromatic Fields.- 7.3.2 Degree of Spatial and Temporal Coherence.- 7.3.3 Measurement of Spatial and Temporal Coherence.- 7.3.4 Relation between Temporal Coherence and Monochromaticity.- 7.3.5 Some Numerical Examples.- 7.4 Directionality.- 7.5 Laser Speckle.- 7.6 Brightness.- 7.7 Higher-Order Coherence.- Problems.- References.- 8 Laser Beam Transformation.- 8.1 Introduction.- 8.2 Transformation in Space. Gaussian Beam Propagation.- 8.3 Transformation in Amplitude: Laser Amplification.- 8.4 Transformation in Frequency: Second-Harmonic Generation and Parametric Oscillation.- 8.4.1 Physical Picture.- 8.4.1.1 Second-Harmonic Generation.- 8.4.1.2 Parametric Oscillation.- 8.4.2 Analytical Treatment.- 8.4.2.1 Parametric Oscillation.- 8.4.2.2 Second-Harmonic Generation.- Problems.- References.- 9 Applications of Lasers.- 9.1 Introduction.- 9.2 Applications in Physics and Chemistry.- 9.3 Applications in Biology and Medicine.- 9.4 Material Working.- 9.5 Optical Communications.- 9.6 Measurement and Inspection.- 9.7 Thermonuclear Fusion.- 9.8 Information Processing and Recording.- 9.9 Military Applications.- 9.10 Holography.- 9.11 Concluding Remarks.- References.- Appendixes.- A Space-Dependent Rate Equations.- B Physical Constants.- Answers to Selected Problems.

Inducing and probing non-thermal transitions in semiconductors using femtosecond laser pulses

Abstract: Soon after it was discovered that intense laser pulses of nanosecond duration from a ruby laser could anneal the lattice of silicon, it was established that this so-called pulsed laser annealing is a thermal process. Although the radiation energy is transferred to the electrons, the electrons transfer their energy to the lattice on the timescale of the excitation. The electrons and the lattice remain in equilibrium and the laser simply 'heats' the solid to the melting temperature within the duration of the laser pulse. For ultrashort laser pulses in the femtosecond regime, however, thermal processes (which take several picoseconds) and equilibrium thermodynamics cannot account for the experimental data. On excitation with femtosecond laser pulses, the electrons and the lattice are driven far out of equilibrium and disordering of the lattice can occur because the interatomic forces are modified due to the excitation of a large (10% or more) fraction of the valence electrons to the conduction band. This review focuses on the nature of the non-thermal transitions in semiconductors under femtosecond laser excitation.

Solid sample introduction by laser ablation for inductively coupled plasma source mass spectrometry

Abstract: The results are described of a preliminary study of the mass spectrometry of solid samples using a ruby laser to ablate the sample into an inductively coupled plasma (ICP) source mass spectrometer. Standard rock samples were used, pelletted with a binder into the form of a disc. Some 200 ablation pits could be accommodated on each sample. Laser pulse energies of 0.3–1 J were used in the fixed Q mode and the ablated material transferred from the ablation cell into the plasma torch by means of the plasma injector gas flow. The mass spectrometer was used in the fixed ion mode using mean ion current detection to evaluate the reproducibility of successive pulses on major constituents and in the scanning mode at the rate of 10 scans s–1 to produce spectra using mean current detection for major elements and pulse counting detection for traces. Problems were experienced with saturation of the detection system in both the mean current and pulse counting modes owing to the transient nature of the sample pulse from the laser, when attempting to quantify major elements, but except where a major peak was saturated, reasonably uniform sensitivity for most elements across the mass range from 7 to 238 m/z was obtained. Isotope ratio measurements were made on lead at 29 µg g–1 and detection limits for the elements examined appear to be 10 ng g–1 or less.

A melting model for pulsing‐laser annealing of implanted semiconductors

Abstract: The transition to single crystal of ion‐implanted amorphous Si and Ge layers is described in terms of a liquid‐phase epitaxy occurring during pulsing‐laser irradiation. A standard heat equations including laser light absorption was solved numerically to give the time evolution of temperature and melting as a function of the pulse energy density and its duration. The structure dependence of the absorption coefficient and the temperature dependence of the thermal conductivity were accounted for in the calculations. In this model the transition to single crystal occurs above a well‐defined threshold energy density at which the liquid layer wets the underlying single‐crystal substrate. Experiments were performed in ion‐implanted amorphous layers of thicknesses ranging between 500 and 9000 A. The energy densities of the Q‐switched ruby laser ranged between 0.2 and 3.5 J/cm2; time durations of 20 and 50 ns were used. The experimental data are in good agreement with the calculated values for the amorphous thickness–energy−density threshold. The model deals mainly with plausibility arguments and does not account for processes occuring in the near‐threshold region or below the melting temperature.

Laser processing and analysis of materials

Abstract: 1 Lasers and Laser Radiation.- 1.1. Introduction.- 1.2. Laser Sources.- 1.2.1. Ruby Laser.- 1.2.2. Nd-YAG Laser.- 1.2.3. Nd-Glass Laser.- 1.2.4. Tunable Infrared Diode Lasers.- 1.2.5. Helium-Neon Laser.- 1.2.6. Argon and Krypton Ion Lasers.- 1.2.7. Helium-Cadmium Laser.- 1.2.8. CO2 Laser.- 1.2.9. Rare Gas Halide Lasers.- 1.2.10. Dye Lasers.- 1.2.11. Stimulated Raman Scattering.- 1.3. Laser Radiation.- 1.3.1. Monochromaticity.- 1.3.2. Beam Shape.- 1.3.3. Beam Divergence.- 1.3.4. Brightness.- 1.3.5. Focusing of Laser Radiation.- 1.3.6. Coherence.- 1.4. Lens Aberrations.- 1.4.1. Spherical Aberration.- 1.4.2. Coma.- 1.4.3. Astigmatism.- 1.4.4. Field Curvature.- 1.4.5. Distortion.- 1.5. Window Materials.- 1.6. Mirrors and Polarizers.- 1.7. Q-Switching.- 1.7.1. Acousto-Optical Q-Switches.- 1.7.2. Electro-Optical Q-Switches.- 1.7.3. Passive Q-Switching.- 1.8. Frequency Conversion.- 1.9. Mode Locking.- 1.10. Detectors and Power Meters.- 1.10.1. Power Meters.- 1.10.2. Radiation Detectors.- 2. Materials Processing.- 2.1. Absorption of Laser Radiation by Metals.- 2.2. Absorption of Laser Radiation by Semiconductors and Insulators.- 2.3. Thermal Constants.- 2.4. Laser Drilling: Heat Transfer.- 2.4.1. Heating without Change of Phase.- 2.4.2. Heating with Change of Phase.- 2.4.3. Experimental.- 2.5. Welding.- 2.5.1. Heat Transfer-Penetration Welding.- 2.5.2. Heat Transfer-Conduction Welding.- 2.5.3. Welding with Multikilowatt Lasers.- 2.5.4. Welding with Low-Power Lasers.- 2.5.5. Laser Spot Welding.- 2.6. Cutting.- 2.6.1. Heat Transfer.- 2.6.2. Cutting Metals.- 2.6.3. Cutting Nonmetals.- 2.6.4. Scribing and Controlled Fracture.- 2.7. Micromachining.- 2.7.1. Resistor Trimming.- 2.7.2. Machining of Conductor Patterns.- 2.7.3. Fabrication of Gap Capacitors.- 2.7.4. Image Recording.- 2.7.5. Laser Marking.- 2.7.6. Micromachining-Thermal Considerations.- 2.8. Surface Hardening.- 2.9. Surface Melting, Alloying, and Cladding.- 2.10. Surface Cleaning.- 2.11. Crystal Growth.- 2.12. Optical Fiber Splicing.- 2.12.1. Optical Fiber-End Preparation.- 2.12.2. Optical Fiber-Drawing.- 2.13. Laser Deposition of Thin Films.- 2.13.1. Evaporation.- 2.13.2. Electroplating.- 2.13.3. Chemical Vapor Deposition.- 2.13.4. Photodeposition and Photoetching.- 3 Laser Processing of Semiconductors.- 3.1. Introduction.- 3.2. Annealing.- 3.3. Annealing-CW Lasers.- 3.4. Recrystallization.- 3.5. Silicide Formation.- 3.6. Ohmic Contacts and Junction Formation.- 3.7. Device Fabrication.- 3.8. Electrical Connections on Integrated Circuits.- 3.9. Monolithic Displays.- 4 Chemical Processing.- 4.1. Introduction.- 4.2. Schemes for Laser Isotope Separation.- 4.3. The Enrichment Factor.- 4.4. Laser-Induced Reaction.- 4.5. Single-Photon Predissociation.- 4.6. Two-Photon Dissociation.- 4.7. Photoisomerization.- 4.8. Two-Step Photoionization.- 4.9. Photodeflection.- 4.10. Multiphoton Dissociation.- 4.10.1. Deuterium.- 4.10.2. Boron.- 4.10.3. Carbon.- 4.10.4. Silicon.- 4.10.5. Sulfur.- 4.10.6. Chlorine.- 4.10.7. Molybdenum.- 4.10.8. Osmium.- 4.10.9. Uranium.- 4.11. Selective Raman Excitation.- 4.12. Economics of Laser Isotope Separation.- 4.13. Laser-Induced Reactions.- 4.13.1. Infrared Photochemistry-Basic Mechanisms.- 4.13.2. Vibrationally Enhanced Chemical Reactions.- 4.13.3. Vibrationally Induced Decomposition.- 4.14. Isomerization.- 4.15. Lasers in Catalysis.- 4.16. Laser-Induced Reactions: UV-VIS Excitation.- 4.17. Processing via Thermal Heating.- 4.18. Polymerization.- 5 Lasers in Chemical Analysis.- 5.1. Introduction.- 5.2. Absorption Spectroscopy.- 5.2.1. Absorption vs. Other Techniques.- 5.2.2. Intracavity Absorption.- 5.3. Laser-Induced Fluorescence.- 5.3.1. Laser-Induced Fluorescence: Theory.- 5.3.2. Laser-Excited Atomic Flame Fluorescence.- 5.3.3. Laser-Excited Molecular Flame Fluorescence.- 5.3.4. Beam Diagnostics.- 5.3.5. Fluorimetry and Phosphorimetry.- 5.3.6. Selective Excitation of Probe Ion Luminescence.- 5.4. Laser-Enhanced Ionization Spectroscopy.- 5.5. Multiphoton Ionization.- 5.6. Raman Spectroscopy.- 5.6.1. Theory and Physical Principles.- 5.6.2. Experimental Techniques.- 5.6.3. Experimental Results.- 5.6.4. Coherent Anti-Stokes Raman Spectroscopy.- 5.7. Laser Magnetic Resonance.- 5.8. Laser Photoacoustic Spectroscopy.- 5.8.1. LPS of Gases.- 5.8.2. LPS of Liquids and Solids.- 5.8.3. Photoacoustic Imaging.- 5.9. Laser Microprobe.- 5.10. Atomic Absorption Spectrometry.- 5.11. Laser Microprobe Mass Spectrometer.- 5.12. Laser Raman Microprobe.- 5.13. Lasers in Chromatography.- 6 Lasers in Environmental Analysis.- 6.1. Propagation of Laser Radiation through the Atmosphere.- 6.2. Laser Remote Sensing of the Atmosphere.- 6.2.1. Absorption Measurements.- 6.2.2. LIDAR.- 6.2.3. Laser Remote Sensing of Wind Velocity.- 6.2.4. Raman LIDAR.- 6.2.5. Differential Absorption LIDAR (DIAL).- 6.2.6. Resonance Fluorescence.- 6.2.7. Heterodyne Detection.- 6.3. Laser Sampling of Aerosols.- 6.3.1. Particle Size and Distribution.- 6.3.2. Particle Composition.- 6.3.3. Interaction of High-Power Laser Radiation with Aerosol Particles.- 6.4. Laser Remote Sensing of Water Quality.- References.- Materials Index.