Chemical Lasers

ISBN-13: 9783642709630 / Angielski / Miękka / 2011 / 370 str.

Nikolay G. Basov; Anatoly S. Bashkin; Valery I. Igoshin

Opis

The rapid development of lasers in the past few decades has led to their application in almost every field of science and technology. The idea that it should be possible to convert the energy released in chemical reactions of chemical lasers directly into coherent radiation resulted in the advent in the 1960s. These first chemical lasers, however, consumed much more energy to initiate the reaction than they emitted. The search for more ef ficient chemical lasing led to the utilization of chain reactions. However, care had to be taken to maintain the appropriate pressure. In 1970, it was demonstrated that the operation of chemical lasers at atmospheric pressure was also feasible, making it easier and cheaper to construct them. One of the advantages of chemical lasers is the wide range of radia tion wavelengths emitted by them: 1.3 - 26 m. The vibrational frequen cies of many molecules fall within this range so that they may convenient ly be used for the operation of such lasers. Progress in the development of chemical lasers is intimately con nected with advances in related fields such as gas dynamics, chemical reaction kinetics, and research into the energy relaxation and transfer processes in molecular systems."

Spis treści

1. Introduction.- 2. Fundamentals of Chemical Laser Kinetics.- 2.1 Qualitative Analysis of Chemical Laser Operation.- 2.1.1 Specific Power of Coherent Radiation.- 2.1.2 Laws Governing Population Inversion.- Development in the Case of Chemical Pumping.- 2.1.3 Energy Characteristics and Their Dependence on the Physico-Chemical Reaction Mechanism.- 2.2 Nonequilibrium Excitation in Chemical Reactions.- 2.3 Population Inversion and Amplification of Radiation in Yibrational-Rotational Transitions.- 2.3.1 Amplification Conditions..- Total and Partial Population Inversion.- 2.3.2 Gain.- 2.4 Elementary Vibrational Relaxation Processes.- 2.4.1 Experimental Data.- 2.4.2 Theoretical Studies.- 2.5 General Equations Describing Physico-Chemical.- Processes Occurring in the Laser Medium.- 2.5.1 Radiative Processes.- 2.5.2 Chemical Kinetics.- 2.5.3 Vibrational-Rotational Kinetics.- 2.5.4 Energy Conservation Equation.- 2.5.5 Generation of Radiation in Gas Flows.- 2.6 Calculation of the Generation and Amplification of Radiation in Multi-Level Chemical Lasers in Quasistationary Approximation.- 3. Kinetics and Numerical Analysis of Chain-Reaction Chemical Lasers (Pulsed Mode).- 3.1 Brief Review of the Theory.- 3.2 H2-F2 System.- 3.2.1 Hydrogen-Fluorine Reaction Mechanism..- Explosion Limits.- 3.2.2 Mathematical Model of the Hydrogen-Fluoride Laser (HFL).- 3.2.3 Calculation of the Effect of Basic Factors on the Energy Characteristics and Emission Dynamics of HFL in the Rotational-Translational Equilibrium Approximation.- 3.2.4 Effect of Rotational Nonequilibrium on Laser Emission Spectrum, Dynamics, and Energy.- 3.2.5 Modeling of HFL with Allowance Made for Rotational Nonequilibrium and Anharmonicity of Lasing Molecules.- 3.3 D2 - F2 - CO2 System.- 3.3.1 Qualitative Discussion of the Kinetic Scheme of Chemical Pumping Involving Energy Transfer.- 3.3.2 Elementary Process Kinetics and Laser Performance Calculation Procedures.- 3.3.3 Calculation of the Effect of Basic Factors on the Energy Characteristics of the DF-C02 Laser.- 3.3.4 Oscillation Excitation and Quenching Mechanism.- 3.3.5 Comparison Between the Energy Characteristics of the H2 - F2 and D2 - F2 - C02 Systems.- 3.3.6 On the Use of Energetic Chain Branching to Initiate Laser Emission with a High Quantum Yield.- 4. Pulsed Chemical Lasers.- 4.1 Requirements for the Parameters of Chemically-Pumped Pulsed Laser Systems.- 4.2 Initiation of Pulsed Chemical Lasers.- 4.2.1 Initiation Techniques.- 4.2.2 Engineering Aspects of Initiation.- 4.2.3 Questions Relating to the Homogeneity of Initiation and the Scaling of the Laser Medium Size.- 4.2.4 Comparison Between Flash-Photolysis and Electron-Beam Initiation Techniques.- 4.3 Laser Mixture Preparation Problems.- 4.4 Non-Chain-Reaction Pulsed Hydrogen-Fluoride Lasers..- 4.5 H2(D2)-F2 Lasers.- 4.5.1 Spectral and Temporal Characteristics.- 4.5.2 Effect of Oxygen and Mixture Preparation Techniques on Laser Performance Characteristics.- 4.5.3 Energy Characteristics.- 4.6 D2 - F2 - CO2 Lasers.- 4.7 Effect of Additives Accelerating the Hydrogen Fluorination Chain Reaction.- 4.8 Beam Divergence in Hydrogen-Fluoride Lasers.- 4.9 Pulsed Chemical Lasers Operating on Vibrational Overtones of HF and DF Molecules.- 4.10 Amplifier-Mode Operation of Pulsed Hydrogen-Fluoride Lasers.- 4.11 High-Repetition-Rate Operation of Chemical Lasers.- 4.12 Pulsed Chemical Lasers Based on Chain Reactions Other than the Hydrogen-Fluorine Reaction.- 4.13 Current Status of Pulsed Chemical Lasers.- 5. Continuous-Wave Chemical Lasers.- 5.1 Physical Principles of Operation of CWCL’s.- 5.2 Purely Chemical Subsonic DF-CO2 Lasers.- 5.2.1 Basic Schemes. Experimental Situation.- 5.2.2 Simplified Theoretical Model..- Discussion of Experimental Data.- 5.2.3 Design-Basis Theoretical Model of Continuous-Wave DF-C02 Laser.- 5.3 Supersonic HF (DF) Lasers..- A Review of Experimental Work.- 5.3.1 Plasma-Generator Laser Version.- 5.3.2 Self-Contained Laser Version.- 5.4 Principal Power Performance Features of Supersonic CWCL’s.- 5.4.1 Introductory Remarks. Flame Front Concept.- 5.4.2 Estimation of Scale Factors.- 5.4.3 Mixture-Pressure Dependence of Laser Energy Characteristics.- 5.4.4 Factors Limiting the Energy Performance of the “Cold”-Reaction HF Laser.- 5.5 Prospects for the Development of the DF-CO2 and HF CWCL’s.- 5.5.1 Supersonic DF-CO2 Laser.- 5.5.2 HF CWCL with Chain Excitation Mechanism.- 5.6 Other Types of CWCL’s.- 5.6.1 Hydrogen-Halide Lasers.- 5.6.2 Continuous-Wave Chemical CO Lasers.- 5.6.3 CWCL’s with Energy Transfer to Polyatomic Molecules.- 5.7 Other Possible CWCL’s Versions.- 5.7.1 Standing-Detonation-Wave HF Chemical Laser.- 5.7.2 16-(im Flowing-Gas DF-CO2 Chemical Laser.- 5.7.3 Continuous-Wave Optical Resonance Transfer HF Laser.- 6. Oxygen-Iodine Chemical Laser - a New Candidate for Engineering Applications.- 6.1 Experimental Results.- 6.2 Singlet Oxygen Generators.- 6.3 Kinetics of the Processes Occurring in the Active Medium of OICL.- 6.4 Pulsed OICUs.- 7. Photon Branching in Chain Reactions and IR-Radiation Initiated Chemical Lasers.- References.

O autorze

Nobelprize winner N. Basov and his collaborators collected in this volume a vast amount of systemized experimental data and of theoretical results on chemical lasers thus placing it inbetween a textbook and a hand- book. The introduction is followed by a presentation of the fundamentals of chemical lasers. Subsequent chapters deal with specific types of chemical lasers including the most recent developments opening the road towards ecologically clean lasers.