In 1916 Einstein introduced a new concept of radiation-matter-interaction known today as stimulated emission of electromagnetic radiation. It then took nearly 40 years before a first practival device based on stimulated emission, the maser, was realized for microwaves in 1954 by Charles Townes, Columbia University, USA.

The extension to shorter wavelengths lasted only several years. In 1960 Theodore Harold Maiman, USA, invented the flash-lamp pumped ruby laser device. He demonstrated for the first time light amplification in the visible spectral range. The observation of laser action with an intense and nearly parallel beam was published first by Collins and colleagues, Bell Laboratories, New Jersey, USA.

Wolfgang Zinth, Ludwig-Maximilian University Munich, and Alfred Laubereau and Wolfgang Kaiser, Technical University of Munich, Germany, report on the long way to the laser followed by the subsequent explosive development of new lasers and fundamental applications. 

Realized some 50 years ago, today the laser effects our every day life via laser based consumer electronics and is a major element of the world of communication network essential for the global economy.

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• The long journey to the laser and its rapid development after 1960,
  W. Zinth, A. Lauereau, W. Kaiser,
  Europ. Phys. J., H 2011.
  DOI: 10.1140/epjh/e2011-20016-0