Introduction

The introductory chapter of this book recounts the evolution of classical and EM theory, discovery of photoelectric effect, and quantum concept of light, leading up to the point when Einstein planted the seed of lasers by conceptualizing the stimulated emission. It then uses revealing illustrations to introduce the concept of population inversion and explains why stimulated emission in conjunction with a population inverted medium only can result in the amplification of light. This chapter also captures the great excitement that followed the birth of laser in 1960 and the controversies that prevail even today, with regard to the allocation of credit on the invention of lasers. Although two (1964 and 1981) Nobel Prizes have been awarded to works leading to the development of lasers, it is strange that Theodore Maiman, credited with the invention of lasers, was ignored by the Nobel committee. The birth of the laser was indeed a giant leap for mankind, and the rest of the chapter provides a glimpse of some of the mind-boggling effects that they exhibit. This book is intended to reflect, in its two parts, the epic journey that lasers have undergone to date.