In my line of work as an editor, I`m often called upon to answer questions from readers or to check my facts as I write and edit for Laser Focus World. We take all the questions from readers very seriously. Of course, it`s quite impossible to answer every question on the spot or to be absolutely certain of every fact in this very rapidly changing field. So we editors rely heavily on a few well-thumbed reference works in our personal libraries. As Theodore Bernstein, the celebrated former copy chief of the New York Times, was fond of saying sternly to errant cub reporters, "You could look it up." Even grizzled old editors need to be reminded to "look it up" from time to time.
And look it up we do. When it comes to lasers and their physics, my two old-faithful reference standbys are The Laser Guidebook, 2nd ed., by Jeff Hecht (McGraw-Hill, New York, NY, 1992) and Principles of Lasers, 4th ed., by Orazio Svelto (Plenum, New York, NY, 1998). These two excellent books deserve a prominent place on your office or laboratory bookshelf. Both of the authors are closely connected with Laser Focus World: Jeff Hecht is a regular contributing editor for the magazine, and Orazio Svelto is a longstanding member of the magazine`s Editorial Advisory Board. Both have written extensively about lasers in the pages of Laser Focus World and elsewhere.
First published in 1976 in Italian as Principi dei Laser, Professor Svelto`s book has become the standard authoritative textbook for a senior-level or first-year graduate course as well as being a reliable reference work. The book has been expertly translated from the Italian by Professor David Hanna of the University of Southampton (England), who is also a member of our Editorial Advisory Board. Orazio Svelto is Professor of Quantum Electronics at the Polytechnic Institute of Milan (Italy) and Director of the Quantum Electronics Center of the Italian National Research Council. He has been an active researcher in laser physics almost as long as lasers have existed. He`s a prolific author of scientific papers and can be seen rushing from session to session at virtually every major laser conference around the world.
Laser behavior simply described
The third edition of Prof. Svelto`s book was published in 1989, and, as he points out in his preface to the fourth edition, there have been many new developments in the field during the last decade so this new edition is almost a new book in its own right. The basic aim of the book remains the same--"to provide a broad and unified description of laser behavior at the simplest level which is compatible with a correct physical understanding," writes Svelto. "The basic philosophy is to resort to an intuitive picture rather than to a detailed mathematical description of the phenomena under consideration," he notes. However, I`d have to say that a good grounding in calculus is needed for a full understanding of Principles of Lasers but, fortunately, much of the more complex math is relegated to an extensive set of appendices.
In particular, the latest edition has a much more extensive account of semiconductor lasers and their performance: quantum-well and multiple-quantum-well devices and vertical-cavity surface-emitting lasers are discussed in some detail, although the quantum cascade laser is only briefly noted as a promising efficient mid-infrared source not requiring cryogenic temperatures. There is also an extended treatment of diode-pumped solid-state lasers in both longitudinal and transverse-pumped configurations with some useful comparisons to lamp-pumped devices. Newer tunable solid-state lasers such as Ti:sapphire and Cr:LiSAF devices are described in some depth.
A key feature of the book is the extensive use of detailed examples of real-world problems frequently based on Prof. Svelto`s own experiences in his laboratories. For instance, in the section on semiconductor lasers, the author shows how to calculate the expected output power and external quantum efficiency of a semiconductor laser. These examples are used throughout the book in addition to many problems given at the end of each chapter. Many of these problems are briefly answered in one of the appendices.
Prof. Svelto`s hefty 600-page book costs almost $60 but it is worth every penny. You should get yourself a copy so "you could look it up" next time you`re unsure of your facts. That will be much easier than trying to reach a hard-pressed Laser Focus World editor.