Table Of ContentDIFFRACTION
GRATINGS AND
APPLlCATlO NS
ERWIH 6. LOEWEH
Spectronic Instruments, Inc.
Rochester, New York
EVGENY POPOV
lnstitute of Solid State Physics
Sofia, Bulgaria
MARCEL
MARCEDLE KKEIRNC, . NEWY ORK BASEL
Library of Congress Cataloging-in-PublicationD ata
Loewen, E. G. (Erwin G.)
Diffraction gratings and applications/ Erwin G. Loewen, Evgeny Popov.
p. cm. - (Optical engineering ; 58)
Includes bibliographical references and index.
ISBN 0-8247-9923-2 (hardcover : alk. paper)
1. Diffraction gratings. 2. Diffraction gratings-Industrial applications.
m.
I. Popov,E vgeny. D. Title. Series: Optical engineering
(Marcel Dekker, Inc.), v.58.
QC4 17.L64 1 997
621.36'14~21
97-2659
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To the Memory
of
Lyuben Mushev
This Page Intentionally Left Blank
From the Series Editor
Our series of books on optical engineering continues tog row in number and in
scope. It is a particular pleasure to bea ble to add this current work to thes eries
becausei t represents a very importantf undamental tool (the diffraction
grating) basedo n the cornerstoneo fw ave optics (diffraction). Since the
diffraction grating is a device or subsystem, it is incorporated into systems and
instrumentst hat allow its versatility tob e expressed in aw ide range of
applications. Of course, I also admit to my own biases, having spent many
years being intrigued and amazed by the beauty and diverse manifestations of
the diffraction of light whether by one-, or three-dimensional structures.
The topic of diffraction gratings and their applications seems forever new in
spite of (or because of) its venerable history. The process of diffraction was
first observed and recorded by Francesco Maria Grimaldi and published in
1665. The diffraction grating didn't arrive on the scene until over one hundred
years later in 1785; it wasd iscovered by the American astronomer David
Rittenhouse. This fact is usually only a footnote in many technical books and
historical treatises because it didn't have much impact. Joseph von Fraunhofer
rediscovered the diffraction grating somewhat by chance. Let me quote from
one ofm y favorite early texts on diffraction (The D#action of Light, X-Rays,
Material Particles by Charles F. Meyer,U niversity of Chicago Press,
1934):
Fraunhofer, in studying the pattern due to a slit, sought to obtain
this pattern with greater intensity. In order to achieve the desired
result he made a series of slits close together by winding a hair
or wire upon a frame. What he then found was not at all what he
had expected. The pattern was not, as he expected, that due to a
single slit only morei ntense; it was thadt ue toa dflaction grating-
he had discovered the diffraction grating. His discovery of the gra-
ting was thus a large extent accidental, but he showed great genius
in the manner in which he followed up on this discovery as well
as in the manner in which he followed up his discoveries of the
sodium line and of the dark lines in the solar spectrum which were
also to ac ertain degree accidental.
. . .
And as that great commentator Walter Cronkite often says, and the rest
"
vi Editor Fro m the Series
ish istory.”A ni mportanth istory, a viablep resent,a nda s trong hture for
diffraction gratings and applications are detailed in this volume.
Brian J. Thompson
Preface
The importance of diffraction gratings in the field of science has never
beene xpressed with more feeling as well as accuracyt h anb y George
Harrison some 50 years ago when he wrote:
“It is diJgicult to pointt o anothers ingled evicet hath asb roughtm ore
importanet xperimentail n formation to every field of sciencet h an the
dinaction grating. The physicist, the astronomer, the chemist, the biologist,
the metallurgist, all use it as a routine tool ofu nsurpasseda ccuracya nd
precision, as a detector of atomic species, to determine the characteristics of
heavenly bodies, the presence of atmospheres in the planets, to studyt he
structures of molecules and atoms, and to obtain a thousand and one items of
information without which modern science wouldb e greatly handicapped.
”
Todayw ec oulda dd to thisl istt he important symbiosist hat exists
between gratings and lasers, which rangefs r omm iniaturec ouplers in
integrated optics to giant gratings for laser pulse compression, not to mention
the millions of tiny transmission gratings that are found in almost every CD-
player, where they serve as beam splitters required for keeping reading heads
inf ocusa ndo n track. The recent discovery that optical fibers can have
diffraction grating structures superimposed has great potential impact the
efficiency and capacity of fiber optics networks.
There exists an enormous literature gratings and their many
applications, spread over dozens of journals and chapters in textbooks, but
only a few monographs, such as Electromagnetic Theory of Gratings, edited
by Petit (1980a )n d Diflaction Gratings by Hutley (1982), and Le
Multiplexage de Longuers d ’Odeb y Laude ( 1992).
Thea im oft hisb ooki s to provide an overview oft h e field of
diffraction gratings and their applications in a single volume. To maintain a
reasonable length many details mustb el eft out, but an attempt is made to
provide a bibliography extensive enough that anybody who wants to follow
a more detailed trail can either find it directly or be led to it, Our aim has
been to reacht hem any users of gratings rather than specialists in their
production.
The booki s m adeu p of three parts: I. Properties of diffraction
gratings, discussed in Chapters 2 to9 ; 11. Diffraction grating treatment,
Chapters 10 to 13; and 111. Diffraction grating manufacture, Chapters 14 to
17. The boundaries between these topics are not always rigid, For example
efficiency behavior depends on groove profile quality, which in turn depends
viii Preface
on manufacturing. Echelles are reflection gratings, but of a special type, and
concave gratings can biebn u lk formo r as waveguides, anSd o me
transmission gratings can reflect totally, etc.
The historical reviewo f Chapter 1 covers the early work in
spectroscopy, mainly in the1 9th century, and other historical aspects are
found in the respective chapters.
Each chapter is designed tob e as self-consistent as possible, but a
reader without experience in this field should start by reading Chapter 2.
Some topics are discussed throughout several chapters, which leads to
repetitions necessary for better understanding and clarity.
No book is conceived in a vacuum. This one began a long time ago
with E. Loewen joining the grating group at Bausch & Lomb, whichw as
started by George Harrison as consultant, David Richardson as the
coordinator and Robert Wiley the mechanical engineer who not only made the
ruling engines work but took a leading part in the many aspects of ruling,
replication and testing of gratings. This included a collaboration of many
years with the ruling development atM IT, where echelles were the main
goal, under George Harrison’s leadership that ended with his death in 1979.
1974 there began a long period of collaboration witht he Laboratoire
d’Optique Electromagnetique, which was based on their pioneering effort to
establish accurate solutions to the problem of energy partition at the surface
of a grating. The key developments were the integral code of Daniel Maystre
and the differential method of Michel Nevibre, and their continued help and
interest ever since is gratefully acknowledged here. The results are especially
visible in Chapters 4 to 6.
The collaboration that ledt o this booko wesi ts origint o Lyuben
Mashev of the Institute of Solid State Physics in Sofia, where he created a
laboratory for holographic gratings. He spent a post-doctoral fellowship with
Bausch & Lombi n Rochester, N.Y., in 1986. The idea of joining in the
writing of a book was first broached by him on a ski lift at nearby Bristol
Mountain. He was the tutor of EvgenyP opov as well as ag reatf riend.
Unfortunately hisu ntimely death in Sofia in 1988 forced a passing of the
torch. We acknowledge here his many contributions and dedicate the book to
his memory.
A decade of collaboration with and within the Laboratoire d’Optique
Electromagnetique in Marseille, where E. Popov has worked since 1993, not
only provided scientific survival, but permitted deeper understanding of many
problems and their detailed analysis.
An important participant in Sofia wasL yubomir Tsonev, who since
1988 contributed his experimental and analytical skills to grating studies. He
had a great role in preparation of Chapter 7. Special thanks are devoted to
Evguenia Anachkova-Scharf, who contributed by locating some rare old
Preface ix
papers in Munich. We also want to acknowledge the staff of the Richardson
GratingL aboratoryo fS pectronic Instruments, Inc., formerly Bausch &
Lomb,w hoh ave given so mucho f their experience ofm any years, and
helped in the preparation of numerous figures. We could single out a few:
Robert WileTy ,o m Blasiak, John Hoose, ChrPis a lmer, and Sam
Zhelesnyak.
Garry Blough devoted many hourst or eviewing the entire text, for
which we are most grateful.
Erwin G. Loewen
Evgeny Popov
