VII. Conclusion

L'ensemble des mthodes pr6cedentes permet ainside mesirer l'indice de rfraction, et accessoirementl'indice d'absorption, pour les solides et les liquides,dans un grand domaine de longueur d'onde, et dans lesregions d'absorption faible ou importante. Ces me-sures presentent un interet multiple. Tout d'abord, laconnaissance de l'indice de rfraction se montre utilepratiquement pour les rgions de transmission lev6e,dans de nombreux cas: substances dispersives, solvantsusuels, couches antir6flechissantes, filtres interf6ren-tiels. A l'int6rieur des bandes, la connaissance desconstantes optiques se montre, th6oriquement, trbsimportante. Elle permet de determiner la valeurexacte des frequences d'absorption, ainsi que l'inten-sit6 d'absorption, et de relier ces grandeurs cellespr6vues par la theorie.

Ces diff6rentes applications ont pris un grand essorces dernibres annes et nous y avons nous-m~mes fourniune contribution non ngligeable 3 " 2 " 8' 9 dont la descrip-tion sortirait du cadre de cette tude.

En conclusion, nos recherches ont permis de com-pl6ter avec succ~s cet important chapitre de l'optique,qui comprend les propriet6s de dispersion et d'absorp-tion des substances, ainsi que leurs applications, et quis'est trouv6 tendu derierement, d'une manibresystematique, du visible au domaine infrarouge. Celui-ci, A cause de son grand nombre d'octaves, et cause dela presence, dans son domaine, de nombreuses bandesfondamentales, permet, beaucoup plus frdquemmentque le visible ou l'ultraviolet, l'etude du ph6nomene

de la dispersion anormale. II offre ainsi un terrainaussi vaste qu'intdressant pour l'etude theorique etexperimentale des proprietds optiques des substances.

Bibliographie1. J. Vincent-Geisse et J. Lecomte, J. phys. radium 21, 794

(1960).2. J. Vincent-Geisse et J. Lecomte, J. phys. radium 20, 841

(1959).3. G. Vagner-Dewulf, J. Vincent-Geisse, et Nguyen Tan Tai,

Rev. optique 39, 578 (1960).4. G. Dewulf, Rev. optique 33, 513 (1954).5. J. Vincent-Geisse, C. R. Acad. Sci. 224, 650 (1947).6. J. Vincent-Geisse, J. phys. radium 9, 175 (1948).7. H. Arzelis, Ann. phys. 2, 181 (1947).8. J. H. Jaffe, H. Goldring, et U. Oppenheim, J. Opt. Soc. Am.

49, 1199 (1959).9. J. Vincent-Geisse et J. Lecomte, C. R. Acad. Sci. 244, 577

(1957).10. J. Vincent-Geisse et J. Lecomte, Rev. optique 37, 295

(1958).11. J. Vincent-Geisse et J. Lecomte, C. R. Acad. Sci. 244, 2152

(1957).12. J. Dayet, Dipl6me d'6tudes sup6rieures, Paris 1961; C. R.

Acad. Sci. 253, 2905 (1962).13. J. Vincent-Geisse, M. Queyrel, et J. Lecomte, C. R. Acad.

Sci. 247, 1330 (1958).14. J. incent-Geisse, M. Queyrel, et J. Lecomte, Revue Uni-

verselle des Mines 15, 507 (1959).15. M. Cameo, C. R. Acad. Sci. 252, 1434 (1961).16. P. Cotton, Ann. phys. 2, 209 (1947).17. G. Dewulf et F. Gans, C. R. Acad. Sci. 243, 1857 (1956).18. M. Cameo et J. Vincent-Geisse, C. R. Acad. Sci. 252, 1579

(1961).19. J. Vincent-Geisse et J. A. Ladd, Spectrochimica Acta 17,

627 (1961).

Oca Activities i20 0

in th.n'Dstereported by STANLEY S. BALLARD, Department of Physics, University of Florida,

Gainesville, Florida. Professor Ballard hopes to receive news and commentsfor this column, which should be sent to him at the above address

One does not have to spend very many minutes looking throughthe present issue of Applied Optics before he realizes that there aretwo quite different types of applications of infrared radiation.The first and best known is to spectroscopy and spectrophotom-etry, in the study and analysis of atoms, molecules, and com-pounds. This is the academic side of the field which is taughtin universities in either chemistry or physics courses, and, on thegraduate level, provides the subject matter for many master'stheses and doctoral dissertations. My column this monthis devoted to the other facet of infrared physics and technology,namely the nonspectroscopic, radiometric type of applicationsoften referred to, for want of a better term, as "field uses." Theimpetus here has come largely from military requirements, andthere has been a tremendous surge of activity since World War II,when infrared devices were first used successfully in actual fieldoperations. The nonmilitary aspects of infrared technology are

also burgeoning, and may eventually outstrip the strictly militaryside if the present trend continues.

Relatively little is taught in college or university courses re-garding the nonspectroscopic aspects of the utilization of infra-red radiation. To be sure, the blackbody radiation laws arecovered in modern-physics courses and perhaps in optics courses.The important subject of radiometry may be touched upon in oneplace or another but is seldom the subject of an entire course,except at the University of Rochester (as stated in my Julycolumn). I understand that Professor E. Scott Barr teaches acourse at the University of Alabama which goes into radiometryand some applications of infrared instruments, but I am not awarethat this sort of thing is done on many campuses-information onother such courses would be received with great interest. Thebook we still refer to here is Measurement of Radiant Energy,edited by W. E. Forsythe (McGraw-Hill, 1937).

September 1962 / Vol. 1, No. 5 / APPLIED OPTICS 585

The need for training along the lines being discussed has be-

come so evident that special concentrated, short summer courses

have been offered at at least three institutions: M I T offered

such a course in the summer of 1954; U C L A has offered a two-

week course for the last two years and is offering a somewhat al-

tered course this summer; the University of Michigan is offer-ing a one-week course in Fundamentals of Infrared Technology

for the fourth year and will give it at two different times this sum-mer, as well as offering an advanced course in special topics.

The students who take these summer courses are largely drawn

from industrial and government laboratories; their desire is to

learn things they need to know in order to do their jobs better.

I am not aware that regular university students take these coursesto an appreciable extent.

Since so many people are having to learn on their own aboutinfrared physics and technology these days, it is well to ask what

instructional material is available for their use. Shortly afterWorld War II, when a number of us realized that this field was

going to grow rapidly, we were concerned about the lack of suit-

able books and other instructional material. Some of us wrotereports and booklets, which unfortunately often bore a security

classification because much of the data on infrared detectors,

radiation from missiles, detection ranges, etc., were then classified

as Confidential or Secret by the military. Perhaps the best

reference in those days was the German book, Das U71trarote

Spectrum, by Schaefer and Matossi (Julius Springer, Berlin,

1930). Unfortunately, this excellent book has never been trans-

lated into English, although a photolithoprint reproduction was

brought out by Edwards Bros. of Ann Arbor, Michigan, in 1943.

The article "Infra-Red Instrumentation and Techniques" by

Van Zandt Williams, published in the Review of Scientific In-

struments [19, 135-178 (1948)], was the first publication to bring

together much of the new data on infrared materials and instru-

ments. I could mention here the several excellent textbooks on

spectroscopic instruments such as Experimental Spectroscopy, by

R. A. Sawyer and Practical Spectroscopy, by Harrison, Lord, and

Loofbourow, but these deal more with the spectroscopic use of

infrared, which is not the primary subject of this column.An excellent treatment of the physical basis for the field ap-

plications of infrared, and one that may not be known to many who

require this information, is "Emission, Transmission, and Detec-

tion of the Infrared," by John A. Sanderson of the Naval Re-

search Laboratory; it is the fifth chapter (pages 126 to 175) of

Guidance, by Arthur S. Locke and collaborators (Van Nostrand,

1955), which is in the series "Principles of Guided Missile De-

sign." In 1957 the Oxford University Press published The

Detection and leasurement of Infra-Red Radiation, by R. A.

Smith, F. E. Jones, and R. P. Chasmar. This book was the first

readily available, detailed, theoretical, and factual treatment of

what is now called infrared physics; its emphasis is largely on de-

tectors of infrared radiation.During the year 1958 it became apparent to many of the leading

workers in the military applications of infrared that much of the

basic information used by them and their associates was in fact

unclassified-after all, it comprised simply physical, chemical, and

engineering data. It was felt that considerable benefit would ac-

crue if there could be an unclassified, widely distributed publica-

tion of as much of this information as possible. This hope was

finally brought to fruition in the Special Issue on Infrared Physics

and Technology of the Proceedings of the Institute of Radio Engi-

neers, Vol. 47, No. 9, September 1959. There are 235 large-sized

pages in double-column format which contain many articles on

infrared physics, technology, systems, and applications. This

volume represents the work of many authors; it was under mygeneral supervision as guest editor of this special issue. On pages

1647-1649 is a short article by W. L. Wolfe of the University of

Michigan, "A Selected Bibliography on Infrared Techniques andApplications," which includes 101 references in the infrared field.

Incidentally, this number of the Proc. IRE was overprinted for

single-copy sale, and I believe that copies can still be obtained by

writing to the IRE at 1 East 79th Street, New York 21, N.Y.The book Infrared Radiation, by Henry L. Hackforth (Mc-

Graw-Hill, 1960) gives an extensive review of the topics ordinarilyincluded in infrared physics and technology. The treatment is

necessarily somewhat superficial, but this book is recommendedfor a rapid review of the field and as a reminder of the many cur-rent applications of infrared radiation. Infrared Methods, Princi-

ples, and A pplications by the English authors G. K. T. Conn andD. G. Avery (Academic Press, 1960) is an unusually detailed and

authoritative treatment of the laboratory techniques used indealing with sources of radiation, optical materials, detectors,amplifiers, and dispersive systems; there are some pages on appli-cations to industrial gas analysis and radiation pyrometry. This

is not a book for the beginner but is an excellent treatment for

those who want to make actual use of infrared techniques in the

laboratory and in the field-it should be regarded as required

reading for such persons.By the later 1950's it must have occurred both to book pub-

lishers and to prospective authors that a more detailed treatmentof infrared physics was due, since several teams of authors startedwriting. The resulting books cover, in general, the five elements

of a practical infrared system, namely the source of radiation,called the target in military parlance; the effect of atmosphericabsorption over the path from the target to the detector; theoptical system; the detector-preamplifier; and finally the read-

out, display, or other output of the system. The first book of acomprehensive nature to appear was Elements of Infrared Tech-

nology, by P. W. Kruse, L. D. McGlauchlin, and R. B. McQuis-tan, all of the Honeywell Research Center (Wiley, 1962). Theirfirst volume, which was published in late January, deals with thegeneration, transmission, and detection of infrared energy; thesecond volume will deal with infrared systems and applications.Fundamentals of Infrared Technology by M. R. Holter, S. Nudel-man, G. H. Suits, W. L. Wolfe, and G. J. Zissis, all of the Univer-

sity of Michigan, was published by Macmillan in June 1962.

This is a one-volume treatment which covers in detail the five

elements of infrared systems just listed. Germane to this column

is Appendix C, "Sources of Information about Infrared Technol-ogy," which is especially recommended to the present readers. I

understand that two more books on infrared are now in prepara-

tion for publication in early 1963. One is by John A. Jamiesonof the Aerojet-General Corporation and his coauthors and givesmore emphasis to statistical considerations. The other is written

particularly for systems engineers who need to know more about

the potentialities and limitations of infrared techniques; it is byRichard D. Hudson, Jr., of the Hughes Aircraft Company.

Thus we see that there is no dearth of descriptive and instruc-

tional material available in the field of infrared physics and tech-nology. If more universities should recognize the need for in-

struction in this modern field of physics and engineering and

should add such courses to their curricula, the instructors would

be able to choose excellent texts and reference books.

586 APPLIED OPTICS / Vol. 1, No. 5 / September 1962