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Lasers: Harnessing the Atom's Light

Articles in Scientific American have for many years set a high standard of presentation alongside a carefully tuned technical level of presentation. To a first approximation, this book reads like a long Scientific American article. Here we have an ambitious attempt to take the reader through a large slice of the history, the physics and the technology of lasers. To that extent the book is perhaps unduly ambitious: a full understanding of such matters requires knowledge in a number of fields - one needs the quantum mechanics of the atom, and the chemistry and band theory of semiconductors, just for starters. And as the lasers get smaller, concepts such as the density of states for electrons in two-dimensional systems become important too. Remarkably, all this material is treated without mathematics, and without any numerical data to speak of. There are beautiful photographs of the emission spectra of several gases, but with no wavelength scale. There are many beautiful photographs and diagrams, but again without numbers. The text does of course redress the balance here, but clearly this is a statement of intent, and of style. We have here a vintage exercise in the discursive, analogy-based style so familiar to readers of Scientific American. The book is therefore a good read, for such readers. Everyone, including physicists, should enjoy the beautiful pictures and the enthusiasm with which the authors tackle the wide variety of subjects they need to cover. On wider issues, it was also pleasing to find some discussion of a question that must have occurred to many in physics: Why did it take so long to discover the laser? But one has to ask the question: Is there a big audience for such a book? A personal view of Scientific American articles over many years is that they generally have lengthy, low-level introductions and are therefore too long. There is something of that here too, which could limit the potential readership. But the authors must nevertheless be commended for having written a totally non-threatening account of one of the most important scientific developments of this century. As a milestone in the public understanding of science, this book is some achievement.