Optical Metamaterials: Fundamentals and Applications , Wenshan Cai and Vladimir Shalaev
Springer, New York, 2009. $129.00 (200 pp.). ISBN 978-1-4419-1150-6
From the late 1960s through the early 1980s, those of us who worked on materials and devices did not use the terms “nano-” and “meta-.” Nor did we have sophisticated tools like the atomic force microscope (AFM), or the bells and whistles of fine-resolution, automated techniques for the manipulation of materials on the nanoscale.
But Wenshan Cai and Vladimir Shalaev do. These authors of Optical Metamaterials: Fundamentals and Applications are highly accomplished in the field of metamaterials, which are used to make such devices as invisible cloaks that bend electromagnetic waves around a shrouded object or superlenses that permit spatial resolution below the diffraction limit. Metamaterials constitute a complex subject: Researchers and students alike need a critical understanding of how the unique properties and applications of those devices depend on the physics, chemistry, and overall properties of optical and electromagnetic components, and on how such components are designed and fabricated.
Optical Metamaterials begins with a brief introduction stuffed with ample references; the remaining chapters extensively cover selected topics: optical properties of metal-dielectric composites; experimental techniques and data treatment; electric and magnetic metamaterials; negative-index materials; applications of nonlinear optics; super resolution with meta-lenses; and optical cloaking.
One stated goal of the authors is to write a textbook for senior undergraduate and graduate courses; indeed, that is quite a commendable and lofty goal for this highly interdisciplinary field! A useful text for advanced undergraduates should, in my opinion, be self-contained, particularly in its presentation of introductory material and unique aspects of a field. It should also systematically develop basic concepts and then elaborate on specific engineering challenges, with worked-out examples. For instance, properties of both exotic and run-of-the-mill metamaterials that might result in a working device must be identified before issues relating to fabrication and characterization are considered.
In its present form, Optical Metamaterials is not self-contained, and I would not recommend it as a textbook, even for graduate courses. Less experienced readers will be forced to rely on cited references to develop an understanding of the structural details of unit cells in metamaterials composites or to derive the design equations that characterize such unit cells. When introducing various design equations and performance trends in optical metamaterials, the book merely references certain seminal papers. It barely touches on the design and synthesis of metastructures that meet specific applications—for example, or those involving two- and three-dimensional arrays, input/output interfaces, packaging—nor does it discuss their reliability and performance in benign and adverse environments.
Readers will also need additional background to understand the book’s comparison of different techniques or processes that are not common knowledge to graduate students or even to nonexpert researchers. The authors frequently mention the AFM and other modern high-resolution characterization and fabrication tools, whose purpose is to correlate a metamaterial’s properties with its micro- and nano-structures; a focus on that correlation was sorely missing in this book. Another concern is the book’s presentation of commercial simulation software: The authors used such programs in their research to elucidate the performance of sought-after metamaterials and devices, but fail to present the codes that were used or to follow up their illustrations with worked-out problems. Such details would have helped the reader grasp the concepts and understand the implications of material choices.
I did enjoy reading Optical Metamaterials for the purpose that best suits it: a useful overview that could encourage researchers new to this multidisciplinary field to dig deeper in pursuing their goals. The chapters are short and well written: They read like summaries of research papers and not like a textbook. Especially well presented and concise are the chapters on negative-index materials and optical cloaking. The book is unnecessarily brief and sketchy at times, though, and may not be as useful for students and researchers who lack sufficient background in materials science and engineering; such readers will need additional resources to acquire a comprehensive understanding of optical metamaterials. That said, a course textbook even for simple, well-developed subjects carries enormous requirements; for a complex interdisciplinary topic like optical metamaterials, with its novel applications, writing such a text is a very tall order indeed.
