Book Review

Fundamentals of Semiconductor Lasers

Takahiro Numai
Springer-Verlag, New York, 2004
259 pp., $119.00 hb
ISBN 0-387-40836-3

Reviewed by Anatoliy Bekrenev

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In Fundamentals of Semiconductor Lasers , Takahiro Numai says that semiconductor lasers have been actively studied and extensively improved since their inception in 1962. These lasers (also known as diode lasers or junction lasers ) are currently the most efficient devices for converting electrical energy into light (their wall-plug efficiency may reach 50%), as well as the smallest lasers yet devised (~1 mm in length). They consist of a p-n junction formed in an elongated gain region, typically in a gallium arsenide crystal, with parallel faces at the ends to serve as partially reflecting mirrors.

The entire laser package is very small and could be incorporated into an integrated circuit board if required. Heterostructure lasers, a more recently developed type of semiconductor laser, include additional layers of different materials of similar electronic configuration, such as aluminum, indium, and phosphorus on the sides of the junction region to minimize current and heat dissipation requirements. By constructing a row of p-n junctions next to each other, all of the separate gain media can be made to produce an effective combined power output.

The author discusses the physics and main characteristics of semiconductor lasers with regard to system applications. First, he reviews the basics of semiconductors, including band structures (bulk structures, quantum structures, and superlattices), optical transitions (excitation, emission, absorption, and optical gains), two- and three-dimensional optical waveguides, and optical resonators. Then he discusses basic operating principles and characteristics of semiconductor lasers, as well as advanced topics, including dynamic single-mode lasers, quantum-well lasers, and control of spontaneous emission.

Numai points out that the applications for semiconductor lasers are primarily in the communications field, in which the near-infrared beams can be transmitted over long distances through low-loss fibers. Lasers' high power and high density of energy make them useful in a wide range of manufacturing processes. These lasers have recently found a large market as the reading device for CD players. They serve as light sources for bar-code readers, CDs, CD-ROMs, magneto-optical discs, DVDs, DVD-ROMs, laser printers, light-wave communication systems, and pumping sources of solid-state lasers.

What this book is lacking, however, is an analysis of the influence of semiconductor structures on the band structures and p-n junction, which would help in understanding the capabilities and limitations of semiconductor lasers. While these structures form the basis for semiconductor lasers, the author does not discuss them in depth. Nor is attention given to problems connected with laser transitions in semiconductors.

Fundamentals of Semiconductor Lasers is a clear and instructive book for advanced undergraduate or graduate students who will become the next generation of laser specialists, and it is a good update for professional physicists, engineers, and researchers in quantum electronics and laser processing. The chapters are largely independent of one another, and a reader who is interested in only one topic may be satisfied by reading all or parts of the relevant chapter without reading the rest of the book. Well written, with many useful figures, formulas, and examples of calculations, Numai's book is a good guide in the field.

Biography

Anatoliy Bekrenev is a professor of physics at National American University (Brooklyn Center, Minnesota). He is currently researching the structure and mechanical properties of materials subjected to laser reactions .