The history of laser - History of laser development

Most people already know what is a laser looks like, straight, thin, powerful, but how laser happens? A laser (Light Amplification by Stimulated Emission of Radiation) is a device that uses an effect of quantum mechanics, induced or stimulated emission, to generate a coherent light beam of a suitable medium and with controlled size, shape and purity.[The history of laser]

In 1916, Albert Einstein laid the foundations for the development of lasers and their predecessors, the masers (which emit microwaves), [The history of laser] using Max Planck's radiation law based on the concepts of spontaneous emission and induced radiation. The theory was forgotten until after World War II, when it was definitively demonstrated by Willis Eugene Lamb and R. C. Rutherford.

In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger constructed the first maser: a device that operated with the same physical principles as the laser but produced a coherent microwave beam. Townes' maser was incapable of running continuously. Nicolay Gennadiyevich Basov and Aleksandr Mikhailovich Prokhorov of the Soviet Union worked independently on the quantum oscillator and solved the problem of obtaining a continuous light output maser using systems with more than two energy levels. Townes, .[The history of laser].Basov and Prokhorov shared the Nobel Prize for Physics in 1964 for "fundamental works in the field of quantum electronics", which led to the construction of oscillators and amplifiers based on the principles of maser-lasers..[The history of laser]

Townes and Arthur Leonard Schawlow are considered the inventors of the laser, which they patented in 1960. Two years later, Robert Hall invents the semiconductor laser. In 1969 is the first industrial application of the laser to be used in the welding of the elements of sheet in the manufacture of vehicles and, the following year Gordon Gould patent many other practical applications for the laser..[The history of laser]

In 1980, a group of physicists from the University of Hull led by Geoffrey Pret recorded the first laser emission in the range of X-rays. Five years later, the compact disc began to be commercialized, where a low-power laser beam "reads" the data coded in the form of small holes (dots and dashes) on an optical disc with a reflecting face. Later that sequence of digital data is transformed into an analog signal allowing the listening of the musical files. Immediately afterwards the technology developed is used in the field of mass data storage. In 1994 in the United Kingdom, laser technology is used for the first time in cinemometers to detect speeding drivers. Subsequently spread its use throughout the world..[The history of laser]

Already in the 21st century, scientists at the University of St. Andrews create a laser that can handle very small objects. At the same time, Japanese scientists create objects the size of a red blood cell using the laser. In 2002, Australian scientists successfully "teleported" a beam of laser light from one place to another. Two years later the laser scanner allows the British Museum to make virtual exhibitions. In 2006, scientists at the company Intel discover how to work with a silicon-based laser chip opening the doors for the development of much faster and more efficient communication networks..[The history of laser]

PROCESSES

Lasers consist of an active medium capable of generating the laser. There are four basic processes that occur in the generation of the laser, called pumping, spontaneous emission of radiation, stimulated emission of radiation and absorption..[The history of laser]

PUMPING

It is caused by a source of radiation such as a lamp, the passage of an electric current or the use of any other type of energy source that causes an emission..[The history of laser]

SPONTANEOUS RADIATION EMISSION

Electrons returning to ground state emit photons. It is a random process and the resulting radiation is formed by photons that move in different directions and with different phases generating an incoherent monochromatic radiation..[The history of laser]

STIMULATED RADIATION EMISSION

The stimulated emission, the basis of the generation of radiation from a laser, occurs when an atom in an excited state receives an external stimulus that causes it to emit photons and thus return to a less excited state. The stimulus in question comes from the arrival of a photon with energy similar to the energy difference between the two states. The photons thus emitted by the stimulated atom have phase, energy and direction similar to those of the external photon that gave rise to them. The stimulated emission described is the root of many of the characteristics of laser light. Not only does it produce coherent and monochromatic light, but it also "amplifies" the emission of light, since for every photon that hits an excited atom another photon is generated..[The history of laser]