Table Of ContentThe Lebedev Physics Institute Series 83
N. G. Basov
Theoretical Problems in
Spectroscopy and Gas
Dynamics of Lasers
THEORETICAL PROBLEMS IN THE SPECTROSCOPY AND
GAS DYNAMICS OF LASERS
TEORETICHESKIE PROBLEMY SPEKTROSKOPII I
GAZODINAMICHESKIKH LAZEROV
TEOPETlfl-lECIDIE IIPOBJIEMbI CIIEHTPOCKOIIMM H
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The Lebedev Physics Institute Series
Editors: Academicians D. V. Skobel'tsyn and N. G. Basov
P. N. Lebedev Physics Institute, Academy of Sciences of the USSR
Recen t Volumes in this Series
Volume 35 Electronic and Vibrational Spectra of Molecules
Volume 36 Photodisintegration of Nuclei in the Giant Resonance Region
Volume 37 Electrical and Optical Properties of Semiconductors
Volume 38 Wideband Cruciform Radio Telescope Research
Volume 39 Optical Studies in Liquids and Solids
Volume 40 Ex perimen tal Physics: Methods and Apparatus
Volume41 The Nucleon Compton Effect at Low and Medium Energies
Volume 42 Electronics in Experimental Physics
Volume 43 Nonlinear Optics
Volume 44 l'iuclear Physics and Interaction of Particles with Matter
Volume 45 Programming and Computer Techniques in Experimental Physics
Volume 46 Cosmic Rays and Nuclear Interactions at High Energies
Volume 47 Radio Astronomy: Instruments and Observations
Volume 48 Surface Properties of Semiconductors and Dynamics of Ionic Crystals
Volume 49 Quantum Electronics and Paramagnetic Resonance
Volume 50 Electroluminescence
Volume 51 Physics of Atomic Collisions
Volume 52 Quantum Electronics in Lasers and Masers, Part 2
Volume 53 Studies in Nuclear Physics
Volume 54 Photomesic and Photonuclear Reactions and Investigation Method with Synchrotrons
Volume 55 Optical Properties of Metals and Intermolecular Interactions
Volume 56 Physical Processes in Lasers
Volume 57 Theory of In teraction of Elemen tary Particles a t High Energies
Volume 58 Investigations in Nonlinear Optics and Hyperacoustics
Volume 59 Luminescence and Nonlinear Optics
Volume 60 Spectroscopy of Laser Crystals with Ionic Structure
Volume 61 Theory of Plasmas
Volume 62 Methods in Stellar Atmosphere and Interplanetary Plasma Research
Volume 63 Nuclear Reactions and Interaction of Neutrons and Matter
Volume 64 Primary Cosmic Radiation
Volume 65 S tellara tors
Volume 66 Theory of Collective Particle Acceleration and Relativistic Electron Beam Emission
Volume 67 Physical Investigations in Strong Magnetic Fields
Volume 68 Radiative Recombination in Semiconducting Crystals
Volume 69 Nuclear Reactions and Charged-P"rticle Accelerators
Volume 70 Group-Theoretical Methods in Physics
Volume 71 Photonuclear and Photomesic Processes
Volume 72 Physical Acoustics and Optics: Molecular Scattering of Light; Propagation of Hypersound; Metal Optics
Volume 73 Microwave-Plasma Interactions
Volume 74 Neutral Current Sheets in Plasmas
Volume 75 Optical Properties of Semiconductors
Volume 76 Lasers and Their Applications
Volume 78 Research in Molecular Laser Plasmas
Volume 77 Radio, Submillimeter, and X-Ray Telescopes
Volume 79 Luminescence Centers in Crystals
Volume 80 Synchrotron Radiation
Volume8! Pulse Gas-Discharge Atomic and Molecular Lasers
Volume 82 Electronic Characteristics and Electron-Phonon Interaction in Superconducting Metals and Alloys
Volume 83 Theoretical Problems in the Spectroscopy and Gas Dynamics of Lasers
Volume 84 Temporal Characteristics of Laser Pulses and Interaction of Laser Radiation with Matter
Volume 86 Superconductivity
Volume 89 Electrical and Optical Properties of III-IV Semiconductors
In preparation
Volume 85 High-Power Lasers and Laser Plasmas
Volume 87 Coherent Cooperative Phenomena
Volume 88 Cosmic Rays in the Stratosphere and in Near Space
Proceedings (Trudy) of the P. N. Lebedev Physics Institute
Volume 83
Theoretical Problell1s in
the Spectroscopy
and Gas Dynall1ics of Lasers
Edited by
N. G. Basov
P. N. Lebedev Physics Institute
Academy of Sciences of the USSR
Moscow, USSR
Translated from Russian by
Donald H. McNeill
SPRINGER SCIENCE+BUSINESS MEDIA, LLC
Library of Congress Cataloging in Publication Data
Main entry under title:
Theoretical problems in the spectroscopy and gas dynamics of lasers.
( Proceedings (Trudy) of the P. N. Lebedev Physics Institute; v. 83)
Translation ofTeoreticheskie problemy spektroskopii i gazodinamicheskikh lazerov.
Includes bibliographical references.
1. Gas lasers-Addresses, essays, lectures. 2. Plasma lasers-Addresses, essays, lec
tures. I. Title: Spectroscopy and gas dynamics of lasers. II. Basov, NikolaI Gen
nadievich, 1922- III. Series: Akademiia nauk SSSR. Fizichesku institut.
Proceedings; v. 83.
QCl.A4114 vol. 83 [QC689] 530'.08s
[535.5'8] 77-17616
ISBN 978-1-4757-6821-3 ISBN 978-1-4757-6819-0 (eBook)
DOI 10.1007/978-1-4757-6819-0
The original Russian text was published by Nauka Press in Moscow in 1975 for the
Academy of Sciences of the USSR as Volume 83 of the Proceedings of the P. N. Lebedev
Physics Institute. This translation is published under an agreement with the Copyright
Agency of the USSR (VAAP).
© 1977 Springer Science+Business Media New York
Originally published by Plenum Publishing Corporation New York in 1977
All rights reserved
No part of this book may be reproduced, stored in a retrieval-system, or transmitted,
in any form or by any means, electronic, mechanical, photocopying, microfllming,
recording, or otherwise, without written permission from the Publisher
PREFACE
This anthology is devoted to the theory of gas and plasma lasers. A considerable portion
is allotted to gas-dynamic lasers. The dependence of their operating characteristics on the
composition of the mixture, the pressure, and the nozzle shape are investigated in detail. Chem
ical gas-dynamic and electrical gas-dynamic lasers, as well as high-temperature electrical
gas-dynamic lasers with free electrons formed as a result of thermal ionization, are discussed.
Far-infrared lasers and the conditions for increasing their efficiency are studied. The feasi
bility of plasma lasers which operate due to rapid cooling of free plasma electrons is demon
strated. The basic types of plasma lasers are examined: electrical (including those using
electron beams), moving plasma (plasma-dynamic and pinch discharge lasers), and plasma
chemical (including the use of molecules with dissociating lower terms). The prospects for
using a multiply charged ion plasma as an intense light source are discussed. Considerable
attention is given to the physical kinetics of the processes involved.
This publication is intended for a large circle of researchers and engineers specializing
in quantum electronics.
CONTENTS
Some Trends in Laser Development.......................... 1
L. A. Shelepin
Introduction. • . . . . . . . . . • . . • . . . • • . • • . . • . . . . . . . . . . . • . • . . . • . . . . . . 1
1. The Physical Kinetics of Lasers. • . . • • . . • . . • . . . . . . . . . . . . . . . . . . . . 1
2. Electrical Lasers Using Vibrational-Rotational Molecular Transitions. . . . . • 4
(a) Continuous Electrical Lasers. . . . • • • . . . . . . . . . • . . . • . . . . • . . . . . 4
(b) Pulsed Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . 5
(c) Electroionization Lasers. . . . • • • • . . . . . . . . • • . . • • . . . . . . . . . . . . 5
(d) TEA Lasers. . . . . . . . . . . • • . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Chemical Lasers .••••......•...........•....•....•........ 5
4. Gas -Dynamic Lasers .........••...............•...•.•...... 6
(a) Chemical Gas-Dynamic Lasers .••........•.......•.•........ 6
(b) Electro-Gas-Dynamic Lasers ....•........•...•.••........•. 6
(c) High-Temperature Lasers ....•.....................•....•. 6
5. Far Infrared Lasers ............•................•......•..• 7
6. Plasma Lasers . . . . . . . . . . . . . . . . . . • . . . . • • . . . . . . . . . . . . . • • • . . 7
(a) Electrical Plasma Lasers. • . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . 7
(b) Moving Plasma Lasers . . . . . • . • • • . . . . . . . . . • • . . . . . . . . . . . . . . 7
(c) Plasma Chemical Lasers. . • . • . . . . • . . . • . . . . . . . • . • . . . . . . . . . . 8
7. The Interaction of Laser Radiation with Matter. The Limits of Applicability
of Population Kinetics. . . . . . . . • • . . . . . . . . . . . . . . . . . . . . . . . . . • 8
Literature Cited. . . . . . . . • . . . . . . . . . . . . . • . . . • . . . . . . • . . . . . • . . . . . . . 8
The Physical Kinetics of Gas-Dynamic Lasers................ 11
A. S. Biryukov
Introduction. . . • • . . • • . . . . . . . . . . . . . . . . . . . . . . . • . . . • . . • . . . • • • . . . • 11
Chapter I
The Problems of Molecular Kinetics. A Review of the Literature. . . . . . . • . • • . • . 12
1. A Brief Review of Published Data on Gas-Dynamic Lasers . . . • . • • • . . . . . • 12
2. The Kinetic Equations for Vibrational Relaxation. . . . . . . • . . . . . • . . . • . • . 14
3. Calculation of Cross Sections for Vibrational Transitions Involving Degenerate
Oscillators. , • . . . . . . . • • . . . . • . • . . . .. • . • . • • . • • • • . • . • • . . . • 22
4. Utilization of Experimental Data on Vibrational Relaxation Times .•..•••... 25
Chapter II
The Physical Kinetics of Gas-Dynamic Lasers. • . • . . . . . . . • . • . . . . . • • . . . . • 27
1. Population Inversion in the Vibrational Levels of CO During Adiabatic
2
Expansion into a Vacuum. . . . . . . • . . . • . • . . . . . • . • . . . . . . . . . • . . 27
vii
viii CONTENTS
2. A Method for Calculating the Vibrational Relaxation of a C~ - N2 - He
Mixture in a Supersonic Nozzle •.•••••.••••••..••••••••...•.• 33
3. A Gas-Dynamic Laser with a Supersonic Nozzle. Effect of the Nozzle Shape on
:e
Laser Operation for To 2500oK .•.••...••••••••••.•.•••••.•. 40
Chapter III
Chemical and Nonequilibrium Vibrational Processes in the Mixtures Used in Gas
Dynamic Lasers. Chemical Gas-Dynamic Lasers .•..•...•••..•••••.. 46
1. Gas-Dynamic Lasers Using Combustion Products ••...•••••••.••.••.. 46
2. Recombination Processes in Molecular Lasers •••.••••••••••••••••.. 49
3. The Mechanism of Nonresonance Vibrational Exchange in Gas-Dynamic
Lasers .......... 52
0 .... III .... 8 III ............ III ...... 0 " .... II ... 0 .. II II .. .. .. .. .. .. .. .. .. .. .. ..
Chapter IV
Electrical and GaS-Dynamic Processes. Electrical Gas-Dynamic Lasers. • • . • . • . • 58
1. Electrical Methods of Producing an Inversion, Their Limitations, and the Role
of Gas Dynamics . • • • . • • • . . . • • • • . • . . . . . • . . . • . • . • • . . • . • . • 58
2. Electrical Gas-Dynamic Lasers . • • • • • . • . • . . • • . . • • • • • . . . • • • • • . . • 62
Chapter V
High-Temperature Gas-Dynamic Lasers • • • • • • • • . • • . . • . • • • • • • • • • • • • • • . 68
1. The Role of Chemical Reactions in the Operation of a Gas-Dynamic Laser. . . • 68
2. Thermal Ionization and High-Temperature Gas-Dynamic Lasers. • • • • • • • . • 72
Chapter VI
Nonequilibrium Processes and Infrared Radiation in the Wake of an Object Flying
through the Upper Atmosphere. • • . . . • . • . • . . . • . • • • • . . • • . • • . • . . . • 73
Literature Cited. . . . . . . . . • • . • . • • • • . • . . . . . . • . • • • • . . . • • • . • . • . . . 83
Electrical Gas-Dynamic Lasers with Thermal Ionization
A. S. Biryukov, V. M. Marchenko, and L. A. Shelepin • . . • . . . • . • • • . • • . • • 89
Literature Cited. • • • • • • • • . • . • • • • • • • • . • • • • • • • • • • . • • • • • . • • • • • • • • • 101
The Theory of Plasma Lasers
L. 1. Gudzenko, L. A. Shelepin, and S. 1. Yakovlenko . • . • • • • • • . . • • . • • • • • 103
Introduction. 1 03
0 III .. '" " .. .. Q .. II " .. .. III .. " III III .. II II " II '" lit .. .. .. II 0 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Chapter I
Relaxation Processes in a Dense, Low-Temperature Plasma. • • • • . • . • • • . • . . • • 104
1. Plasma Lasers and Problems in Kinetics. . • • . . • • • • • . . • • • • • . • . • • . . • 104
2. The Probabilities of Elementary Processes . • • • • • . . . • • • . • • . • . . • • • . . 105
(a) Radiative Transitions. . . • • • • • . • . . . • • • • . • . . . . . . • • • • • . . • • • • 105
(b) Collisions with Electrons. • • . • • . . • • . . . • • . • • . • • • . • • • • • • . • . . • 106
(c) Dissociative Recombination •••••.•.•••••••.••.' • • • • • • • . • • • • . 107
(d) Collisions with Heavy Particles • • . • • • • • • • • • • • • • • . • • • . • • • • . • • 107
3. Population and Temperature Relaxation Equations • • . • . • • • • . . • • . . • . . • • 107
(a) The Equations for the Populations. • . • . • • • • • • . • • • • • • • • • • . • • • • • 108
(b) The Thermal Balance Equations • • • . • • • • • • • • • • • • • . • . • • • • • • • . . 109
4. Population Relaxation. Basic Approximations. • • • • • • • • . • • • • . • . • . • • • • 109
(a) The Constant (or stationary) Sink Approximation. • . • • . • • . . . • . . • • • • 109
(b) The Single-Quantum Approximation. . • . • • • . • • . • • • . • . • • • • . . • • . . 111
(c) The Diffusion Approximation • • • • . . • • • • • • • • • • • • • • • • • • • • • • • . • 112
(d) The Preferred-Sink Approximation. • • • . . • • • • • • • • . • • • • • • . . • • • • 112
ix CONTENTS
Chapter II
Plasma Lasers . • • • • . • . • • . . • . • • . • • . . . . • • • • . • • . • • . • . . • • • • • . • • . • 113
5. Ionization (Gaseous Discharge) Lasers. • • • • • . • • • . • • . • . . . • • • . . • • . . • 113
6. Recombination (Plasma) Lasers . . • . . • • • • • • . • . . • • • • . • • . . • • . • . • • • 116
Chapter III
Recombination Mechanisms for Population Inversion in Atoms and Ions. • • • • • • • . • 11 7
7. Population Inversion in a Plasma of Simple Chemical Composition. • • • • • . • • 117
(a) Radiative Depopulation of the Lower Working Level. • • • • • . • • • • • • • • • 118
(b) Deexcitation by Electrons . • • . • . • • • . . • • • • • • • • • • • • • . • • • • • • • • 118
8. Plasma with Two Chemical Constituents. • • . • • • . • . • • • • . . • • . • • • • 119
(a) Effect of an Impurity on the Character of the Nonequilibrium. • • . • . • • • • 120
(b) The Population Inversion. . • • . . • • • • • • • • • • • . • . • • • • • • • • • • • • • • 121
Chapter IV
Atomic and Ionic Plasma Lasers. . . . • . . • . • • • . • . • . . . . • • • . • • . . • . . . . . • • 123
9. Lasing in the Afterglow of an Electric Field Pulse. • • • • • • • • • • • . • . • • • • . 123
10. Continuously Pumped Plasma Lasers. • • • • • • • • . • . . • • • • . • • • • • • • . • . . 126
(a) Electron Beam Plasma Lasers. • . • • • • • • • • • • • • • • • • • • • • • • • • • . • 128
(b) Atomic Reactor Laser. . • • • • . • • • • . • • • • • • . • • • • • • • • • • • • • • • • • 128
11. Lasing in a Moving Plasma. . . • • • • . • • • • . • . . • • • • • • • • • • • • • . . . • . • 129
(a) Plasma-Dynamic Lasers. • • • . • . . . • . • • • • • • . . • • . . • • • • . • • • • • . 129
(b) Compressed Plasma Lasers. . • . . • • • . • • • • • • . • . . • . • • • . • . • • . • • 131
(c) Plasma Jets. MHD Lasers. • • . . • • • • . • • . • • • . • • . • . • • • • • • • • • • • 131
Chapter V
Plasma Chemical Lasers. • . . . . . • . • . • • . • • • • • . • . . . • . . • . . • • • . . . • . . • . 132
12. Chemical Depopulation of Lower Atomic Levels. . • . . . • • • • • . • • • • • . . • . • 132
13. Plasma Lasers Using Disintegrating (Dissociating) Molecules. A Scheme for
Filling an Excited State. Conditions for Amplification • • • • • • . • • • • • . . 134
(a) Relaxation Channels. . . . . . . . . . . . . . . . . . • . • . • . . . • . • . . • . 135
(b) Ideal Case. • . • • • . • . . • • • • • • • • . • • • • • • . • . • . . • • • • • . • . • • • • . 136
(c) Conditions for Amplification. • . • • . • • • • . . . . . . . . • • . • • . . • . • • • • • 137
14. Problems in Making Plasma Lasers Using Dissociating Molecules. . • • • . • • • 138
Chapter VI
Short-Wavelength Plasma Lasers. • . • . • . • • • • . • • • • . • . • . • • . • • • • • . • • • • • 141
15. Vacuum Ultraviolet Lasers. • • • . • . • . • . . • • • . . . . . . . . . • . . • . . . • • • • 141
15. The X-Ray Laser Problem. • • . • • • • . • • . • • • . . • • • • • • • • • • • • • • • • • • • 143
(a) The Power Source for an X-Ray Laser. . . . • . . • . . . . • . . • . • . . • • . • • 143
(b) The Principle of Creating an Inverted Population. Composition of the
Medium . . . . • • • • • • . . • • • • • • • • • • . . . . • • . . . . • • • . . • • • . • 144
(c) Conditions for Energy Input. . • • . • . • . • • • • • • . • • • • • • • • • • . • • • • . 144
Literature Cited. • . . • • • • . . • . • . . . . • • • . • . . . . . . . . . . . . . . . . . . . . . . . • . 145
The Kinetic s of P las m a and Rot at ion a 1 Trans it ion L as e r s ••••• 151
S. A. Reshetnyak
Introduction ••••••••.•. 151
Chapter I
Rotational Kinetics and Far Infrared (FIR) Molecular Lasers •••••.•.•••••• 152
0 0 •
1. Rotational Kinetics of Diatomic Molecules . • . • . . . . . . . . . . . . . . • • . • . • . 152
2. Lasing on Transitions of Multiatomic Molecules (Far Infrared
and Submillimeter Ranges) •.......•..•...•.....•••..•...• 159
0 •
x
CONTENTS
3. Rotational Energy Distribution Functions and Rotational Transition Lasers
(Discrete Model) ...•...•...••................•....... 163
Chapter II
Quasistationary Population Distribution Functions in Low-Temperature Plasma 167
1. The Level Population Distribution Function for Hydrogen • • • • • . • • • • • • • • • 167
2. Level Populations in Atoms. Plasma Lasers. • • . • • • • • . • • • • • • • • • • • • • 177
3. The Level Population Distribution Function of Atoms in Mixtures. • . • • • • • • • 180
Chapter III
The Kinetics of Moving Plasma Lasers . • • . • • • • • • • • . . . • • • • • • • • • • • • • • • • 185
1. Plasma-Dynamic Lasers. • . . • • • • • • • • . • . • . • • . • • • • • • • . . • • • • • • • • 185
2. Pinch Discharge Lasers . . • . • • . • . • • • • . • • • • • • • • . • • • • • • • • . • • . • • 193
Chapter IV
Some Problems in the Kinetics of Plasmas with Multiply Charged Ions • • . • . . • . . • 199
1. The Physical Processes in a Hot" Plasma and Their Uses. . • • • • • • . . • . • • 199
If
2. An Analysis of High Current Discharges with a Return Current • • . • • • • • • • • 202
3. The Theory of a High Current ac Pinch Discharge. . • • • . . • • • • • • • • • . • . • 207
4. The Ionization State Distribution Function in a Multiply Charged Ion Plasma.
Laser-Produced Plasmas •••...•.••.... 212
Conclusion • . . . . . • • . . • • . • ..•.•••••••• 219
Literature Cited •.•.•.•.••....•••••••.•••.•• 219
