Since the demonstration of a small ruby rod crossing the threshold of laser emission in 1960 by TheodoreMaiman half a century ago, there has been a tremendous revolution in the development of wide variety oflasers, vastly improved laser performance. The Laser science, over the years has been playing importantroles in scientific research, instrumentation, consumer products, optical communications, materialprocessing, biomedical application, medicine, and a host of many new applications. In more specific terms,a lion’s share of demand and R&D lends to communications and information systems, almost one quartergoes to materials works, and a huge other requirements owe to medical sectors and defense applications.The present-day lasers have been possible through a long journeybeginning with the understanding ofelectromagnetic waves and energy-frequency relationship of radiation by put forward by Planck in 1900followed by Einstein’sidea of stimulated emission in 1917 which led to demonstration of ammonia maserconceived in 1951 and demonstrated in 1954 by Charles Hard Townes Columbia University. Laterdevelopments went through realization of microwave solid-state maser in 1956 by Nicolaas Bloembergenof Harvard University, predictingmasers operation in the optical and infrared regions in 1958 by Townes, aconsultant for Bell Labs, and Arthur L. Schawlow reported in Physical Review Letters, patenting theoptical maser by them in March 1960 and finally by Theodore H. Maiman, a physicist at Hughes ResearchLaboratories in Malibu, California, constructed the first ruby laserin May 1960. Today, we have lasersranging from gas, solid-state semiconductors based on innumerable variety of design and working principletill the amazing invention of quantum well lasers and fiber lasers and many more.

   Notably, laser-related discovery led to 19 Nobel prizes. In the 1960s, laser beams reached the Moon. It isthe laser beams that mapped Mars and the Moon. It is needless to recall that lasers arenow integral parts oftoday’s technological human civilization sitting atthe very heart of the internet, transmittinglight signalsthrough the fiber cables that constitute the backbone of world-wide communications network.

   In this tutorial we intend to focus on the chronological development of laser with an understanding of basicphysics of operation and technological developments to meet a range of unique application as well assolving many unforeseen scientific problems. The overall discussion will be of immense use for thegraduate and undergraduate students and researchers in the field of broad area of laser optics andphotonics.