Table Of ContentQUANTUM ELECTRONICS-PRINCIPLES AND
APPLICATIONS
EDITED BY
PAUL F. LIAO
Bell Communications Research, Inc.
Red Bank, New Jersey
PAUL L. KELLEY
Lincoln Laboratory
Massachusetts Institute of Technology
Lexington, Massachusetts
A complete list of titles in this series appears at the end of this volume.
DYE LASER PRINCIPLES
With Applications
Edited by
F J. Duarte
Eastman Kodak Company
Research Laboratories
Rochester, New York
Lloyd W. Hillman
Department of Physics
The University of Alabama in Huntsville
Hunstville, Alabama
ACADEMIC PRESS, INC.
Harcourt Brace Jovanovich, Publishers
Boston San Diego New York
London Sydney Tokyo Toronto
This book is printed on acid-free paper. ©
Copyright © 1990 by Academic Press, Inc.
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.
ACADEMIC PRESS, INC.
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United Kingdom Edition published by
ACADEMIC PRESS LIMITED
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Library of Congress Cataloging-in-Publication Data
Dye laser principles / edited by Frank J. Duarte, L.W. Hillman.
p. cm. — (Quantum electronics—principles and applications)
Includes bibliographical references.
ISBN 0-12-222700-X (alk. paper)
1. Dye lasers. 2. Quantum electronics. I. Duarte, Frank J.
II. Hillman, Lloyd William, date. III. Series.
QC688.D94 1990
621.36'64— dc20 89-17912
CIP
Printed in the United States of America
90 91 92 93 9 8 7 6 5 4 3 2 1
Contributors
The numbers in parentheses indicate the pages on which the authors'
contributions begin.
M.A. Akerman (413), Oak Ridge National Laboratory, Oak Ridge, Ten-
nessee 37831
J.-C. Diels (41), Department of Physics and Astronomy, University of New
Mexico, 800 Yale Boulevard, North East, Albuquerque, New Mexico 87131
F.J. Duarte (1,133,239), Photographic Research Laboratories, Eastman
Kodak Company, Kodak Park, B-59, Rochester, New York 14650-1744
Leon Goldman (419), U.S. Naval Hospital, Balboa Park, San Diego,
California 92134
Lloyd W. Hillman (1, 17), Department of Physics, The University of Ala-
bama in Huntsville, Huntsville, Alabama 35899
Leo Hollberg (185), National Institute of Standards and Technology, Boul-
der, Colorado 80303
Guilford Jones II (287), Department of Chemistry, Boston University,
Boston, Massachusetts 02215
David Klick (345), Massachusetts Institute of Technology, Lincoln Labora-
tory, Lexington, Massachusetts 02173-0073
ix
Preface
The dye laser is a remarkable and highly versatile source of tunable
coherent radiation. Its success and importance are demonstrated by its
wide applicability. From basic science, such as physics and spectroscopy, to
medicine and industry, the dye laser has been shown to be an extremely
flexible and useful tool. In this book, a number of topics representative of
dye laser research and development are considered and discussed. The
treatment starts with basic principles of coherence and propagation and
then considers the physics and technology of ultrashort pulse generation.
The design and theory of dispersive narrow-linewidth pulsed oscillators is
then followed by a detailed description of continuous wave dye lasers and a
discussion on the technology of pulsed dye lasers. Next, attention is fo-
cused on the molecular structure and photophysics of dyes. The book
concludes with three additional chapters on industrial applications, laser
isotope separation, and medical applications.
It is important to indicate that many of the topics considered here
transcend dye lasers and are applicable to lasers in general and other areas
of quantum electronics.
The style of presentation is determined by our attempt to write at a level
appropriate to seniors and graduate students. However, extensive refer-
ences given in most of the chapters should also make this book attractive to
current researchers.
During the gestation period of this volume, it has been our pleasure to
work and interact with a fine group of contributors. Certainly, they should
be given credit for all the good features of this book. As editors, we assume
responsibility for any shortcomings.
Finally, we would like to thank J. Donaldson for compiling and verify-
ing the references of some chapters. Also, one of us (F. J. D.) is particu-
larly grateful to the U.S. Army Missile Command (Redstone Arsenal,
Alabama) for funding some of the work discussed in this book.
F.J. Duarte
Lloyd W. Hillman
xi
Chapter 1
INTRODUCTION*
F.J. Duarte
Photographic Research Laboratories
Photographic Products Group
Eastman Kodak Company
Rochester, New York
and
Lloyd W. Hillman
Department of Physics
The University of Alabama in Huntsville
Huntsville, Alabama
1. INTRODUCTION 1
2. BRIEF HISTORICAL SURVEY 3
2.1. Pulsed Dye Lasers 3
2.2. Continuous-Wave Dye Lasers 5
2.3. Ultrashort Pulse Dye Lasers 5
2.4. Laser Dyes 6
3. AIMS OF THIS BOOK 7
3.1. Book Organization 7
3.2. Additional Topics 9
4. CHALLENGES TO DYE LASERS 10
REFERENCES 1 1
1. INTRODUCTION
Dye lasers are perhaps the most versatile and one of the most successful
laser sources known today. Indeed, at the time of the discovery of this class
of lasers by Sorokin and Lankard (1966), few could have anticipated their
spectacular diversification and their significant contribution to basic phy-
sics, chemistry, biology, and additional fields.
*The brief historical section was compiled with the help and cooperation of J.-C. Diels,
G. Jones, and L. Hollberg.
Dye Laser Principles: With Applications 1 Copyright © 1990 by Academic Press, Inc.
All rights of reproduction in any form reserved.
ISBN 0-12-222700-X
2 F.J. Duarte and Lloyd W. Hillman
Dye lasers offer to researchers both pulsed and continuous wave (cw)
operation that is tunable from the near-UV to the near-IR. Such versatility
emerges from the large choice of molecular dye species available (see
Appendix) coupled with the wide variety of excitation sources (see, for
example, Table 6.1 in Chapter 6). A closer examination of dye-laser
characteristics highlights the availability of the following output modes:
(i) Tunable cw oscillation from —400 to —1000 nm.
(ii) Very stable cw single-mode operation at linewidths less than 1 kHz
(see, for example, Hough et al. (1984)).
(iii) Tunable pulsed oscillation from —320 to —1200 nm.
(iv) Conversion efficiencies exceeding 50% for some pulsed laser-
pumped dye lasers (see, for example, Morey (1980), Bos (1981)).
(v) High pulse energies. A single coaxial flashlamp-pumped dye laser
has been reported to yield 400 J in a lO-^ts pulse (Baltakov et al.,
1974), and an excimer laser-pumped dye laser has been reported to
produce 800 J in a 500-ns pulse (Tang et al., 1987).
(vi) Ultrashort pulses: 27 fs (Valdmanis et al., 1985).
(vii) Very long pulses (well into the μ$ regime under flashlamp
pumping).
(viii) High pulse repetition frequency (prf): in excess of 10 kHz under
copper vapor laser excitation (see, for example, Duarte and Piper
(1984)).
(ix) High average powers. The ability of dye lasers to operate at high
average powers is partly due to its liquid state, which facilitates the
important process of heat removal. Single flashlamp dye lasers have
been reported to provide up to 200 W of average power (Mazzinghi
et al., 1981), and a flashlamp-pumped system has demonstrated
1.4 J per pulse at 850 Hz (—1.2 kW average) (Morton and Drag-
goo, 1981). The copper-laser-pumped dye-laser system at the Law-
rence Livermore National Laboratory has demonstrated output
powers in the 600-800-W range (Paisner, 1989).
(x) Broad bandwidths.
(xi) Narrow-linewidth pulsed operation including single-longitudinal-
mode oscillation at low and high prf (see, for example, Littman
(1978), Saikan (1978), Bos (1981), Bernhardt and Rasmussen
(1981), Duarte and Piper (1984)).
This unique flexibility furnishes many economic and engineering design
advantages. Emission at any particular wavelength is achieved by simply
changing the dye, which offers significant savings in capital and operating
cost. Also, numerous alternatives are available in system integration.
1. Introduction 3
Further testimony of the success of the dye laser can be provided by a
broad listing of its applications:
(i) industrial applications,
(ii) medical applications,
(iii) military applications,
(iv) large-scale laser isotope separation (LIS),
(v) study of fundamental physics,
(vi) numerous types of spectroscopy techniques,
(vii) laser radar as well as light detection and ranging (lidar).
The large number and wide range of dye-laser applications certainly pro-
vide proof of their flexibility and versatility.
In this introduction, we limit the discussion to some aspects of broad
interest in dye-laser physics and technology.
2. BRIEF HISTORICAL SURVEY
The field of dye lasers offers a rich and extensive literature. In this
regard, we note that Magyar (1974) in his classified bibliography of journal
dye-laser publications for the early period of 1966-1972 included 454
references! This number represents only publications in the infancy of dye
lasers. It is our opinion that a fair historical perspective requires a thorough
consideration of a large number of publications. Such proper chronological
review is beyond the scope of this introduction.
In this section, we provide a limited and brief historical description of
the field of dye lasers as illustrated by the following subfields: pulsed dye
lasers, cw dye lasers, ultrafast dye lasers, and laser dyes.
2.1. Pulsed Dye Lasers
The first dye laser was the ruby laser-pumped dye laser introduced by
Sorokin and Lankard (1966). This report was quickly followed by the
papers of Schäfer et al. (1966) and Spaeth and Bortfeld (1966). Shortly
afterward, dye-laser excitation at shorter wavelengths utilizing second
harmonic emission from solid-state lasers, such as ruby and neodymium,
was reported (see, for example, Sorokin et al. (1967), Soffer and McFar-
land (1967), Schäfer et al. (1967), Kotsubanov et al. (1968, 1969), Wallace
(1971)).
The use of the nitrogen laser as a direct UV excitation source for dye
lasers was reported by several authors within a short period (Lankard and
von Gutfeld, 1969; Lidholt, 1970; Capelle and Phillips, 1970; Myer et al.,
1970; Broida and Haydon, 1970). The excimer laser was introduced as a
4 F.J. Duarte and Lloyd W. Hillman
dye-laser pump a few years later via the KrF laser (see, for example,
Sutton and Capelle (1976) and Godard and de Witte (1976)) and the XeCl
laser (see, for example, Uchino et al. (1979)).
Laser-pumped oscillator-amplifier configurations were introduced by
Hänsch et al. (1971) and Itzkan and Cunningham (1972).
High-prf operation of dye lasers was demonstrated using a copper-vapor
laser as an excitation source by Hargrove and Kan (1977) and Pease and
Pearson (1977). These authors reported dye-laser oscillation at a prf of
6 kHz.
The first flashlamp-pumped dye laser was reported by Sorokin and
Lankard (1967) and Schmidt and Schäfer (1967). Flashlamp-pumped dye
lasers were operated in an oscillator-amplifier configuration by Huth
(1970) and Flamant and Meyer (1971). A master-oscillator forced-
oscillator arrangement was described by Magyar and Schneider-Muntau
(1972).
Frequency doubling of tunable dye-laser radiation using an ADP crystal
was introduced by Bradley et al. (1971) and Dunning et al. (1972). Raman
shifting of dye-laser emission utilizing compressed hydrogen was an-
nounced by Schmidt and Appt (1972).
Dye lasers in the solid state were introduced by Soffer and McFarland
(1967) and Peterson and Snavely (1968). Lasing of dyes in the vapor phase
has also been reported (see, for example, Steyer and Schäfer (1974)).
In the area of frequency selectivity, the following developments may be
considered important:
(i) mirror-grating resonator (Soffer and McFarland, 1967),
(ii) mirror-grating resonator in conjunction with an intracavity étalon
(Bradley et al., 1968),
(iii) multiple-prism tuning (Strome and Webb, 1971; Schäfer and Mül-
ler, 1971),
(iv) telescopic narrow-linewidth resonator (Hänsch, 1972).
(ν) single-prism expander (Myers, 1971; Stokes et al., 1972; Hanna
et al., 1975),
(vi) pressure tuning of telescopic dye-laser resonator (Wallenstein and
Hänsch, 1974),
(vii) grazing-incidence narrow-linewidth resonator (Shoshan et al., 1977;
Littman and Metcalf, 1978),
(viii) multiple-prism laser-beam expansion (Novikov and Tertyshnik,
1975; Klauminzer, 1978; Wyatt, 1978; Duarte and Piper, 1980),
(ix) synchronous tuning of grazing-incidence dye laser (Liu and Litt-
man, 1981),
(x) prism preexpanded grazing-incidence oscillator (Duarte and Piper,
1981),
1. Introduction 5
(xi) dispersion theory of multiple-prism laser-beam expansion (Duarte
and Piper, 1982),
(xii) analytical and numerical design of achromatic multiple-prism laser-
beam expanders (Barr, 1984; Duarte, 1985; Trebino, 1985),
2.2. Continuous-Wave Dye Lasers
The first cw dye laser was demonstrated by Peterson et al. (1970). These
authors utilized rhodamine 6G dye excited by the 4p 4D —> 4s2P
5/2 3/2
transition (at 514.5 nm) of an Ar ion laser.
Important developments in cw dye-laser technology include the demon-
stration of a three-mirror folded cavity system by Kohn et al. (1971), the
introduction of the dye jet by Runge and Rosenberg (1972), and the report
on the use of biréfringent filters (Bloom, 1974).
One of the unique features of the cw dye laser is its ability to provide
tunable single-frequency oscillation (see, for example, Hercher and Pike
(1971) and Barger et al. (1973)). A further important landmark has been
the demonstration of very stable single-longitudinal-mode operation at
subkilohertz linewidths (Drever et al, 1983; Hough et al, 1984).
Efficient high-power operation of single-frequency cw dye lasers has
been reported by Schröder et al. (1977) and Jarrett and Young (1979). The
latter authors reported single-frequency oscillation at an output power of
0.9 W using rhodamine 6G and an Ar ion laser pump providing 4 W at
514.5 nm. Johnston et al. (1982) reported on a stabilized single-frequency
ring dye-laser system yielding 5.6 W using rhodamine 6G dye and a
24 W Ar ion laser pump. This dye laser was designed to provide continuous
wavelength coverage throughout the visible spectrum using several dyes.
The wavelength range of cw dye lasers has been extended to the UV
spectral region using harmonic and sum frequency generation (see, for
example, Blit et al. (1978)). Pine (1974) utilized mixing in LiNb0 to
3
obtain tunable radiation in the infrared.
2.3. Ultrashort Pulse Dye Lasers
Passive mode locking in pulsed solid-state lasers, using liquid-saturable
absorbers, was first reported by Mocker and Collins (1965) in a ruby laser
and by DeMaria et al (1966) in a Nd 3+ glass laser. Self-mode locking
in a rhodamine 6G flashlamp-pumped dye laser, using the saturable
absorber 3,3'-diethyloxadicarbocyanine iodide, was reported by Schmidt
and Schäfer (1968).
Passive mode locking in a cw dye laser was described by Ippen et al
(1972). The colliding pulse concept was introduced by Ruddock and Brad-
ley (1976), and it was applied to a ring dye laser by Fork et al (1981) who
