Light and light based technologies have played an important role in transforming our lives via scientific contributions spanned over thousands of years. In this book we present a vast collection of articles on various aspects of light and its applications in the contemporary world at a popular or semi-popular level. These articles are written by the world authorities in their respective fields. This is therefore a rare volume where the world experts have come together to present the developments in this most important field of science in an almost pedagogical manner. This volume covers five aspects related to light. The first presents two articles, one on the history of the nature of light, and the other on the scientific achievements of Ibn-Haitham (Alhazen), who is broadly considered the father of modern optics. These are then followed by an article on ultrafast phenomena and the invisible world. The third part includes papers on specific sources of light, the discoveries of which have revolutionized optical technologies in our lifetime. They discuss the nature and the characteristics of lasers, Solid-state lighting based on the Light Emitting Diode (LED) technology, and finally modern electron optics and its relationship to the Muslim golden age in science. The book’s fourth part discusses various applications of optics and light in today's world, including biophotonics, art, optical communication, nanotechnology, the eye as an optical instrument, remote sensing, and optics in medicine. In turn, the last part focuses on quantum optics, a modern field that grew out of the interaction of light and matter. Topics addressed include atom optics, slow, stored and stationary light, optical tests of the foundation of physics, quantum mechanical properties of light fields carrying orbital angular momentum, quantum communication, and Wave-Particle dualism in action.

The laser, initially called the "optical maser," was proposed in 1958 by Charles Townes and Arthur Schawlow; in 1960, Theodore Maiman was the first among several researchers to achieve laser oscillation by using a ruby crystal. In the following quarter of a century, a considerable amount of re search and development has taken place, and the laser is now utilized for many diverse applications, ranging from the commonplace compact disk to intricate surgical applications in medicine. Since I first entered the laboratory of Professor Yasuharu Suematsu in 1962 to complete my thesis, I have been studying the new field of laser optics. In spite of many expectations and a vast investment in research, the first practical use of lasers was difficult to of Univ. Erlangen once jokingly achieve. The late Professor K. H. Zchauer remarked that laser was defined by an English physicist as "Less Application of Stimulated Expensive Research. " In a similiar vein, Dr. Herwig Kogelnik reminded me that in the early 1960s, maser was often called "Money Acqui sition Scheme for Expensive Research. " Initially I worked with a ruby laser, then with a helium-neon-gas laser, and am presently engaged in semiconductor laser research. There are proba bly not a large number of researchers who have had the opportunity to build these three representative types of lasers. My primary objective of study lies in optical communications however, and therefore, I have been approaching the laser mainly as a lightwave propagator.