Vertival-cavity surface-emitting lasers (VCSELs) are one of the most promising new developments in laser physics. Covering such a wide range of topics such as operation principles, design considerations and performance measurements, this book is the first of its kind in that it provides readers with a comprehensive account of the latest technological developments in VCSEL devices. In fact, all the chapters are written by pioneers and key experts who have exclusive access to the most up-to-date innovations in the respective fields. Readers will come to appreciate to all the crucial aspects of VCSEL devices. Theories and simulations as well as experiments are discussed in the book.