Tight focus on a fast-shifting topic

These two texts are excellent additions to the student literature on lasers and optics. I can see myself using both regularly in our MSc course and in final-year optional courses for undergraduates. David Sands's book on diode or semiconductor lasers is a specialised text that deals with all the aspects of these lasers that students need to consider and covers basics of semiconductor physics through to the principles of the most advanced semiconductor lasers.

William Chang's book takes a different approach and places more emphasis on the propagation of optical waves and treats all lasers with what he calls a unified approach, emphasising generic principles and characteristics. His book targets US postgraduates, but much of the material could be used in final-year undergraduate courses in Europe.

There is continuous change and development in the subject. Advances are not merely incremental; there are frequent radical innovations that need to find their way into university courses quickly. This is particularly the case with diode lasers. Sands deals effectively with this fact. He includes substantial chapters on newer topics such as the vertical cavity surface-emitting, high-power diode, blue, quantum-dot and quantum-cascade lasers.

Chang's emphasis on fundamental concepts is based on long-established principles of electromagnetic theory. Indeed, as he says, many topics he addresses, such as guided wave modes in planar and cylindrical geometrics, are covered in other books. What makes his book special is the refreshingly concise presentation, which conveys the essence of a concept or a mathematical approach without compromising precision.

It is clear that Chang has taught this material often, and his enthusiasm is apparent. He anticipates student concerns and takes the discussion through to completion. However, physics students may be a little surprised to discover a section introducing the principles of quantum mechanics a full 150 pages into the book. One has to get to the use of the density matrix to recognise the need for such an introduction, but then one recognises that it does make the chapter self-contained.

Unfortunately, neither Sands nor Chang includes worked examples. Chang presents no problems for students to tackle; Sands offers a few. That said, most course tutors prefer to set their own.

Advanced course books such as these two are also valuable for PhD students and postdoctoral researchers. Both books are organised in such a way that they can be used as reference texts.

Gareth Parry is professor of applied physics, Imperial College London.