Antsiferov V.V., Smirnov G.I. Physics of solid-state lasers (ISBN 1898326177) (CISP, 2005)(179s)
.pdf
Physics of
Solid-State
Lasers
V. V. Antsiferov and G. I. Smirnov
Cambridge International Science Publishing Ltd.
PHYSICS OF SOLID-STATE
LASERS
PHYSICS OF SOLID-STATE
LASERS
V V ANTSIFEROV and G I SMIRNOV
CAMBRIDGE INTERNATIONAL SCIENCE PUBLISHING
Published by
Cambridge International Science Publishing
7 Meadow Walk, Great Abington, Cambridge CB1 6AZ, UK http://www.cisp-publishing.com
First published 2005
© V V Antsiferov and G I Smirnov
Conditions of sale
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 1-898326-17-7
Printed and bound in Great Britain by Lightning Source UK Ltd
Contents
Preface ....................................................................................................................... |
v |
Introduction ............................................................................................................. |
vii |
Chapter 1 |
|
Solid-state chromium lasers in free lasing regime ........... |
1 |
1.1 SPECTROSCOPIC CHARACTERISTICS OF ACTIVE MEDIA ON |
|
CHROMIUM IONS .......................................................................................... |
1 |
1.2 EXPERIMENTAL METHODS OF EXAMINING FREE LASING PA- |
|
RAMETERS ...................................................................................................... |
2 |
1.2.1 Experimental equipment ................................................................................ |
2 |
1.2.2 Methods of eliminating technical perturbations of the resonator of a pulse
solid-state laser .................................................................................................. |
3 |
1.2.3 Methods of producing quasi-stationary lasing ............................................. |
6 |
1.2.4 The methods of selection wavelength tuning of the radiation wave ........... |
9 |
1.3 RUBY LASERS ................................................................................................ |
10 |
1.3.1 Spectral–time characteristics of free lasing TEMooq in a laser with flat |
|
mirrors .............................................................................................................. |
11 |
1.3.2 Single-frequency adjustable quasistationary lasing in a laser with flat |
|
mirrors .............................................................................................................. |
16 |
1.3.3 Energy parameters of lasing ........................................................................ |
18 |
1.3.4 Lasing parameters of TEMmnq modes in a laser with spherical mirrors
19 |
|
1.4 ALEXANDRITE LASERS .............................................................................. |
26 |
1.4.1 Spectral–time lasing parameters ................................................................. |
27 |
1.4.2 Energy parameters of lasing ........................................................................ |
30 |
1.5 Emerald lasers .................................................................................................. |
32 |
1.6 CHROMIUM LASERS IN RARE-EARTH–GALLIUM GARNETS ........ |
36 |
1.6.1 Spectral–time parameters of lasing ............................................................. |
37 |
1.6.2 Energy parameters of lasing ........................................................................ |
39 |
1.7 LASER ON CHROMIUM IONS IN A CRYSTAL OF POTASSIUM- |
|
SCANDIUM TUNGSTATE ............................................................................ |
40 |
1.7.1 Spectral and energy parameters of lasing .................................................. |
41 |
i
1.8 OPTIMISATION OF THE ENERGY CHARACTERISTICS OF RADIA- |
|
TION OF CHROMIUM LASERS ................................................................ |
42 |
Chapter 2 ................................................................................................................. |
45 |
Solid-state neodymium lasers in free lasing |
|
regime ............................................................... |
45 |
2.1 SPECTROSCOPIC CHARACTERISTICS OF ACTIVE MEDIA ON |
|
NEODYMIUM IONS ..................................................................................... |
45 |
2.2 NEODYMIUM GLASS LASERS .................................................................. |
46 |
2.2.1 Spectral–time lasing parameters ................................................................. |
49 |
2.2.2 Energy parameters of lasing ........................................................................ |
51 |
2.3 ND:YAG LASERS ............................................................................................ |
52 |
2.3.1 Spectral–time parameters of free lasing in pulsed regime ....................... |
53 |
2.3.2 Energy parameters of lasing in pulsed regime ........................................... |
57 |
2.3.3 Spectral–time and energy characteristics of lasing in continuous regime58 |
|
2.4 ND LASERS ON GADOLINIUM–SCANDIUM–GALLIUM GARNET |
|
WITH CHROMIUM ...................................................................................... |
62 |
2.4.1 Spectral–time characteristics of radiation ................................................. |
64 |
2.4.2 Energy parameters of lasing ........................................................................ |
66 |
2.5 ND-DOPED LANTHANUM BERYLLATE LASERS ................................. |
67 |
2.5.1 Spectral–time parameters of lasing ............................................................. |
67 |
2.5.2 Energy parameters of lasing ........................................................................ |
69 |
2.6 ND LASERS IN HEXA-ALUMINATES OF LANTHANUM-MAGNE- |
|
SIUM AND LANTHANUM–BERYLLIUM ................................................ |
70 |
2.6.1 Spectral and time parameters of lasing ...................................................... |
71 |
2.6.2 Energy parameters of lasing ........................................................................ |
72 |
2.7 ND LASERS ON POTASSIUM–GADOLINIUM AND POTASSIUM– |
|
YTTRIUM TUNGSTATES ............................................................................ |
73 |
2.7.1 Spectral–time parameters of lasing ............................................................. |
74 |
2.7.2 Energy parameters of lasing ........................................................................ |
77 |
2.8 ND LASERS ON SELF-ACTIVATED CRYSTALS ..................................... |
77 |
2.9 OPTIMISATION OF THE ENERGY CHARACTERISTICS OF RADIA- |
|
TION OF PULSED ND LASERS .................................................................. |
79 |
2.10 PROBLEM OF NON-ATTENUATING PULSATIONS OF RADIATION |
|
IN SOLID-STATE LASERS ........................................................................... |
80 |
Chapter 3 ................................................................................................................. |
83 |
Generation of powerful single-frequency giant |
|
radiation pulses in solid-state lasers ............. |
83 |
3.1 METHODS OF PRODUCING SINGLE-FREQUENCY LASING IN |
|
LASERS WITH Q-FACTOR MODULATION ........................................... |
83 |
3.2 POWERFUL SINGLE-FREQUENCY TUNABLE RUBY LASER WITH |
|
INJECTION OF THE EXTERNAL SIGNAL ............................................. |
85 |
i i
3.3 POWERFUL SINGLE-FREQUENCY TUNABLE ND-DOPED LASERS
WITH INJECTION OF THE EXTERNAL SIGNAL ................................ |
89 |
3.4 SINGLE-FREQUENCY TUNABLE ND LASERS WITH PASSIVE Q- |
|
MODULATION ............................................................................................... |
92 |
3.4.1 Energy and spectral characteristics of radiation ....................................... |
93 |
3.5 SINGLE-FREQUENCY TUNABLE ALEXANDRITE LASER WITH |
|
PASSIVE Q-MODULATION ........................................................................ |
94 |
3.5.1 Experimental equipment .............................................................................. |
96 |
3.5.2 Spectral–time and energy parameters of lasing ........................................ |
98 |
Chapter 4 ............................................................................................................... |
100 |
Lasing of stable supershort radiation pulses in
solid-state lasers ............................................ |
100 |
4.1 METHODS OF PRODUCTION OF STABLE SUPERSHORT RADIA- |
|
TION PULSES ............................................................................................... |
102 |
4.1.1 The method of decreasing the number of lasing modes .......................... |
103 |
4.1.2 The method of injection of the external signal ......................................... |
103 |
4.1.3 The method of the regime of the second threshold .................................. |
103 |
4.1.4 The method of the self-stabilisation regime .............................................. |
104 |
4.1.5 The method of introducing additional losses ............................................ |
105 |
4.2 LASING OF STABLE SUPERSHORT PULSES OF RADIATION BY THE |
|
METHOD OF INJECTION OF THE EXTERNAL SIGNAL ................. |
105 |
4.3 LASING OF STABLE SUPERSHORT RADIATION PULSES BY THE |
|
METHOD OF INTRODUCING INTRA-RESONATOR LOSSES ......... |
108 |
4.3.1 Experimental equipment ............................................................................ |
109 |
4.3.2 Parameters of supershort radiation pulses ................................................ |
111 |
CHAPTER 5 ......................................................................................................... |
115 |
Increasing the lasing efficiency of .................... |
115 |
solid-state lasers ............................................. |
115 |
5.1 INCREASING PUMPING EFFICIENCY .................................................. |
116 |
5.1.1 Selective pumping of the active medium ................................................... |
117 |
5.1.2 Laser pumping ............................................................................................. |
118 |
5.1.3 Laser diode pumping .................................................................................. |
118 |
5.2 INCREASING THE CONCENTRATION OF IMPURITY ACTIVE IONS |
|
120 |
|
5.3 SENSITISING OF LASER SOLID-STATE MEDIA ................................. |
121 |
5.4 CROSS RELAXATION AND STEPPED SYSTEMS OF PUMPING |
|
LASER TRANSITIONS ............................................................................... |
123 |
5.5 LOW-THRESHOLD SOLID-STATE MEDIA ........................................... |
125 |
5.6 EXPANDING THE SPECTRAL RANGE OF LASING ............................ |
126 |
5.7 INCREASING THE BEAM STRENGTH OF SOLID-STATE MEDIA . 127
iii
5.8 NEW OPTICAL CIRCUITS OF SOLID-STATE LASERS ...................... |
128 |
Chapter 6 ............................................................................................................... |
130 |
Principles of lasing of solid-state lasers .......... |
130 |
6.1 QUANTUM KINETIC EQUATION FOR THE DENSITY MATRIX .... |
130 |
6.2 EQUATIONS FOR THE ELECTROMAGNETIC FIELD ....................... |
133 |
6.3 MODELLING OF LASER SYSTEMS ........................................................ |
134 |
6.4 FREE LASING ............................................................................................... |
139 |
6.5 THE GIANT PULSE REGIME ................................................................... |
142 |
Chapter 7 ............................................................................................................... |
145 |
Stochastic and transition processes in solid-state |
|
lasers ............................................................... |
145 |
7.1 STATISTICAL MODELLING OF LASING .............................................. |
145 |
7.2INITIAL AND NON-LINEAR STAGES OF THE LASING PROCESS . 148
7.3ANALYSIS OF THE RELATIONSHIP BETWEEN THE LASING CONDITIONS AND FLUCTUATIONS OF THE DURATION OF THE TRAN-
SITION PROCESS ....................................................................................... |
150 |
7.4THE STATISTICAL MODEL OF THE EXCITATION OF LASING IN THE ABSENCE OF INITIAL THERMODYNAMIC EQUILIBRIUM 153
7.5TRANSITION PROCESSES AT SLOW CHANGES OF THE LASING
PARAMETERS ............................................................................................. |
156 |
Index ...................................................................................................................... |
165 |
i v
2HAB=?A
In the book, attention is given to the processes of interaction of coherent radiation with solids, the physical relationships governing the generation of laser radiation in dielectric crystals and glasses, activated by luminescent admixtures. Because of their compact form, longevity, and a large number of radiation parameters, solid-state lasers on crystals and glass are used most widely in science and technology in comparison with other types of laser. The most attractive feature of the solidstate lasers as sources of coherent radiation, is the large variety of the lasing conditions, with the typical features including the different conditions of free lasing, passive and active synchronisation of modes, the giant pulse regime. Because of the influence of nonlinear selfeffect of radiation, additional nonlinear-optical elements in laser resonators make it possible to control the lasing parameters, including the realisation of new lasing conditions. The expansion of the sphere of application of the solid-state lasers is associated with both the improvement of the technology of formation of new solid-state active media and with the development of new highly efficient methods of controlling laser radiation.
In the monograph, we examine in detail the problem of selforganisation of the radiation of solid-state lasers, describe the theoretical fundamentals of simulation of stochastic processes in the interaction of coherent electromagnetic radiation with the solid, and the principles of statistical nonlinear lasing dynamics. The physical mechanisms of the methods of controlling the radiation of solid-state lasers in the free lasing and giant pulse conditions are described, together with the method of synchronisation of pulses, stabilisation and optimisation of the parameters of solid-state lasers in order to produce powerful monochromatic radiation with adjustable frequency.
The examined general relationships of the physics of solid-state lasers are illustrated by the results of a large number of investigations of the spectral-time, angular and energy characteristics of lasing of lasers on chromium ions in ruby, alexandrite, gadolinium–scandium–
v