Laser device generates a strong narrow beam of clear light so thin that it can be focused to a very small spot. The principle on which the Laser is manufactured is to create an environment where all atoms can send out their light at one time at the same direction. Laser beams are of different sizes, from the size of a grain to a huge building. They have certain remarkable properties, which make them chromatic. Laser light consists of light of only one colour while sunlight is a combination of seven colours. Laser is very coherent and can be directed or aimed over very long distances, without the beam spreading. It also has the advantage that a lot of power is concentrated in a very small area.

The basic process for laser action named ‘Stimulated emission’ was first put forward by Albert Einstein in 1917. But the history of laser started in 1957 when two scientists Arthur L. Schawlow and Charles H. Townes invented Maser a device that came before Laser. They published scientific paper titled ‘Infrared and Optical Masers’ in 1958, regarding using stimulated emissions to investigate gases for breaking up of light into the colours of a spectrum. Hence they received the patent for the invention of the Laser. In 1964 Townes received the Nobel Prize and later in 1981 Schawlow also rewarded with the Nobel Prize for their contribution to the development of Laser.

The first man to produce a pulse of clear and orderly light from a Laser with the use of a medium was Theodore Maiman. In 1960 he produced the Laser light with ruby as the medium. In 1961 Ali Javan, an American Physicist built a helium-neon gas laser. In 1965 Lasers were used to create the first two colour photographic image and in 1966 liquid lasers were built. In 1970s laser beams were used to form electronic circuit patterns on ceramics. The smallest semiconductor lasers were introduced in 1991 and two years later self-focused lasers were used. Quantum Cascade or QC lasers appeared in 1994. They operated like an electronic waterfall and used in electrical transmission in the fields of communication. 

As laser beams are easily affected by rain, fog, low clouds; so scientists introduced metal tubes, specially designed mirrors and thermal gas lenses to protect it. But these mediums could not provide complete protection. Hence in 1970s fibre optics was used to enable lasers to send out telephone signals.

Lasers in medical field were used only when Kumar Patel of Bell Laboratories made carbon dioxide laser in 1964. Surgeons carried out complicated operations with laser beams. Japan developed a blue short wave laser in 1988, which is being used to store and read a large amount of information on Compact Discs (CDs). In 1989 the IBM (USA) produced the smallest laser of the world in the form of cylinders with thickness of 1/10 of human hair.

Today there are lasers of different wavelengths and of different powers. Some of the well-known lasers are Ruby, Nel, Yah, CO2, e-Ne, Argon, Diode laser etc. A laser can be divided into 3 main parts- (1) the medium (the material that is used to produce the beam such as a ruby crystal or gas) (2) the power source that energizes the medium (3) the resonator to make the beam more effective.

Lasers are now widely being used in communications, computers, medicinal, meteorology, construction and industrial sectors. They are used in industries for drilling precise holes, as well as for cutting and welding metals.  They are indispensable in medical field for surgery and stone removal from kidney without operation. They reduce the loss of blood during and after surgery as they seal blood vessels. Lasers also help in quick and natural healing. Shorter lasers are being used to join detached retinas of eyes. They are also used to treat highly malignant type of skin cancer. Lasers are the most essential part of scanners, laser printers and compact disc players. They are also used to produce special effects in the movies, theatres, concerts and light shows.