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Polaritons
Solid State Communications, Vol. 19, P. 281, 1976.
Pergamon Press.
Printed in Great Britain
BOOK REVIEW
Polaritons. Editors, E. Burstein and F. De Martini, Proceedings of the first Taormina Research Conference on the Structure of Matter, pp. 401, 205 illus., Pergamon Press, 1975, Price $20,00, £8.50. The basic idea of a polariton mode a mixed excitation mode of the coupled radiation and matter polarization fields was introduced in 1951 by Huang. He discussed how lattice vibrations of ionic crystals which carry a dipole moment are coupled to the electromagnetic waves propagating in the crystal, and form mixed excitation modes, partly phonons and partly photons, which have a characteristic dispersion relation. The name “polariton”, however, came somewhat later, after theoretical work by Fano, Hopfield and Pekar led to the recognition that similar mixed modes arise from the coupling of the radiation field to the electronic excitations of a crystal as well. Since the characteristic frequencies of the vibrational modes and of the electronic excitations of dielectric media the excitons are well separated, it is usual in the literature to distinguish phonon—polaritons and exciton—polaritons. Later also the coupled magnetic dipole excitation—photon modes in magnetic media came to be known as polaritons. It is then clear that the physics of polaritons encompasses a large portion of the physics of elementary cxcitations in solids, and that it is therefore a central topic of theoretical and experimental solid-state research. A volume intended to offer an updated broad overview of the main directions of research in this field is therefore most welcome. Conference Proceedings, by their very nature, tend to be somewhat fragmented into highly specialized con—
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tributions, and apart from a few introductory review papers, are generally of little help to the novice trying to become familiar with the subject. The editors found an excellent way to enlarge the scope of these Proceedings and their prospective audience, by reprinting, at the end of the volume, twelve key papers from the literature. Although the choice of the papers is, in a few instances, somewhat peculiar (we wish to point out here a major omission: the 1956 paper by U. Fano), the reprint section is going to be very useful to the newcomer trying to orient himself in the various branches of contemporary polariton research. The original papers cover all major areas presently under investigation, from surface moes to nonlinear optical properties, from magnetoplasmaphoton modes to the theoretical problems of crystal optics with spatial dispersion. The fifty or so contributions are very loosely grouped together by topic. It would have probably been more helpful to the reader to organize them under five or six chapters or sections, possibly beginning each of them with the papers, like those of A.S. Barker on dispersion of polariton modes, of D.L. Mills on spatial dis. persion, or of E. Burstein and co-workers on surface polaritons which have a more pronounced review or introductory character. Nevertheless, this volume is likely to become not only a good reference source for the specialist, but possibly also a useful guide to the student trying to find his way in the maze of recent literature.
281
M. ALTARELLI University ofillinois at Urbana Champaign —
Pergamon Press.
Printed in Great Britain
BOOK REVIEW
Polaritons. Editors, E. Burstein and F. De Martini, Proceedings of the first Taormina Research Conference on the Structure of Matter, pp. 401, 205 illus., Pergamon Press, 1975, Price $20,00, £8.50. The basic idea of a polariton mode a mixed excitation mode of the coupled radiation and matter polarization fields was introduced in 1951 by Huang. He discussed how lattice vibrations of ionic crystals which carry a dipole moment are coupled to the electromagnetic waves propagating in the crystal, and form mixed excitation modes, partly phonons and partly photons, which have a characteristic dispersion relation. The name “polariton”, however, came somewhat later, after theoretical work by Fano, Hopfield and Pekar led to the recognition that similar mixed modes arise from the coupling of the radiation field to the electronic excitations of a crystal as well. Since the characteristic frequencies of the vibrational modes and of the electronic excitations of dielectric media the excitons are well separated, it is usual in the literature to distinguish phonon—polaritons and exciton—polaritons. Later also the coupled magnetic dipole excitation—photon modes in magnetic media came to be known as polaritons. It is then clear that the physics of polaritons encompasses a large portion of the physics of elementary cxcitations in solids, and that it is therefore a central topic of theoretical and experimental solid-state research. A volume intended to offer an updated broad overview of the main directions of research in this field is therefore most welcome. Conference Proceedings, by their very nature, tend to be somewhat fragmented into highly specialized con—
—
—
—
tributions, and apart from a few introductory review papers, are generally of little help to the novice trying to become familiar with the subject. The editors found an excellent way to enlarge the scope of these Proceedings and their prospective audience, by reprinting, at the end of the volume, twelve key papers from the literature. Although the choice of the papers is, in a few instances, somewhat peculiar (we wish to point out here a major omission: the 1956 paper by U. Fano), the reprint section is going to be very useful to the newcomer trying to orient himself in the various branches of contemporary polariton research. The original papers cover all major areas presently under investigation, from surface moes to nonlinear optical properties, from magnetoplasmaphoton modes to the theoretical problems of crystal optics with spatial dispersion. The fifty or so contributions are very loosely grouped together by topic. It would have probably been more helpful to the reader to organize them under five or six chapters or sections, possibly beginning each of them with the papers, like those of A.S. Barker on dispersion of polariton modes, of D.L. Mills on spatial dis. persion, or of E. Burstein and co-workers on surface polaritons which have a more pronounced review or introductory character. Nevertheless, this volume is likely to become not only a good reference source for the specialist, but possibly also a useful guide to the student trying to find his way in the maze of recent literature.
281
M. ALTARELLI University ofillinois at Urbana Champaign —