Thisisthe?rstbookinworldliteraturedevotedtoapplicationsoftheisotopic e?ect in solids. It is accessible to physicists, chemists, electronic engineers, and material scientists alike. This book is intended both as tutorial and as reference. Readers seeking to learn the basics of application of the isotopic e?ect in solids should start by reading the ?rst few overview chapters, and then dig into descriptions of speci?c applications to see how they really work. It is hoped that it will be useful to undergraduate and graduate students of physics and optics as well as engineers, physicists, material scientists, and medical doctors who are interested in investigation or applications of the isotopic e?ect in solids. This book is a state-of-the-art introduction to very recent activity in solid-state physics which has developed in the main during the last half century and promises a new technology of isotopic engineering. Important applications are to be expected for information storage and dev- oping materials for computer memory, quantum computers, isotopic ?bers, isotopic optoelectronics, and quantum electronics as well as UV lasers. The references I cite are those with which I am most familiar and which have helped us understand the subject as presented here. There has been no attempttogivecredittoeachcontributor,butIhavetriedtocitetheoriginal papers, which brought new and important results (methods) to applications of the isotopic e?ect in solids, covered in this text.

1 Introduction.- 2 Phonon Spectra of Solids: Indicator of Their Isotope Purity.- 2.1 Theory of Lattice Dynamics.- 2.2 Elastic Properties.- 2.3 Vibrational Properties.- 3 Thermal Properties.- 3.1 Dependence of the Thermal Conductivity on the Isotopic Composition.- 3.2 Lattice Constant Dependence on Temperature and Isotopic Composition.- 4 Isotopic Renormalization of the Electronic Excitation Energy Spectrum.- 4.1 Exciton States.- 4.2 Exciton-Phonon Interaction.- 4.3 Giant Isotopic Effect in the Energy Spectrum of Wannier-Mott Exciton in LiH Crystals.- 4.4 Nonlinear Dependence of Band-Gap Energy on the Isotopic Effect.- 4.5 Renormalization of Binding Energy of Wannier-Mott Excitons by Isotopic Effect.- 4.6 Nonlinear Dependence of Binding Energy on Isotopic Concentration.- 4.7 Isotopic Effect in the Luminescence Spectrum.- 5 Process of Self-Diffusion in Isotopically Pure Materials and Heterostructures.- 5.1 General Remarks.- 5.2 The Relation of Diffusion Experiments to the Mathematics of Diffusion.- 5.3 The Self-Diffusion Process.- 5.4 The SIMS-Technique.- 5.5 Self-Diffusion of Li and H in LiH Crystals.- 5.6 Self-Diffusion in Intrinsic Ge.- 5.7 Self- and Interdiffusion of Ga and Al in Isotopically Pure and Doped Heterostructures.- 6 Neutron Transmutative Doping.- 6.1 The NTD Process: A New Reactor Technology.- 6.2 Reactor Facilities for Transmutative Doping.- 6.3 Nuclear Reaction Under the Influence of Charged Particles.- 6.4 Nuclear Reaction Under the Action of the ?-Rays.- 6.5 Nuclear Reactions Under the Influence of Neutrons.- 6.6 The Influence of Dopants.- 6.7 Atomic Displacement Effects in NTD.- 6.8 Experimental Results.- 7 Optical Fiber.- 7.1 Optical Communication.- 7.2 Maxwell's Equations.- 7.3 Geometric Optics of Fibers.- 7.4 Waveguide Mode Propagation.- 7.5Pulse Spreading.- 7.6 Materials for Optical Fibers.- 7.7 Fiber Preparation.- 7.8 Isotopes in Fibers.- 8 Laser Materials.- 8.1 Some General Remarks.- 8.2 Absorption and Induced Emission.- 8.3 Semiconductor Lasers.- 8.4 Nonlinear Properties of Excitons in Isotopically Mixed Crystals.- 9 Other Unexplored Applications of Isotopic Engineering.- 9.1 Isotopic Information Storage.- 9.2 Isotopic Structuring for Fundamental Studies.- 9.3 Other Possibilities.- 10 Conclusion.- References.