Lasers
The laser is a device that a beam of light that is both scientifically and practically of great use because it
is coherent light.
Lasers consist of several components a few of the many things that so-called active medium consists of
are, atoms of gas, molecules in a liquid, and ions in a crystal. Carbon monoxide, helium-cadmium,
hydrogen-fluoride, iodine, excimer, color center, and rare gas-halide lasers are just a few of many types
of lasers there are out there in the world. The helium-neon laser is the most common and by far the
cheapest costing about $170. The diode laser is the smallest being packed in a transistor like package.
The dye laser are very good for their broad, continuously variable wavelength capabilities. The theory of
simulated emission was first proved by Albert Einstein in 1916, Then population inverse was discussed
by V. A. Fabrikant in 1940. This led to the building of the first ammonia maser in 1954 by J. P. Gordon, H.
J. Zeiger, and Charles H. Townes.
Lasers are possible because of the way light interacts with electrons. Electrons exist at specific energy
levels or states characteristic of that particular atom or molecule. The energy levels can be imagined as
rings or orbits around a nucleus. Electrons in outer rings are at higher energy levels than those in inner
rings. Electrons can be bumped up to higher energy levels by the injection of energy-for example by a
flash of light.
Types of lasers in more detail
There are various types of lasers and the classification is based on the pumping or excitation scheme of
the laser systems. Their shapes and sizes are also varies from the tip of a needle to the size of
multistoried buildings. The large classes of lasers include optically pumped lasers, Gas-discharge lasers,
pulsed gas lasers, Photo dissociation lasers, Chemical lasers and high powered-short pulse lasers. Some
can operate continuously, while a few can produce pulse which can last only for a few days.
Bibliography:
Bertolotti, M., Masers and lasers: An Historical Approach (1983)
Wikipedia: Laser physics
Learning about lasers with Veritasium/Axis is awesome (Yt)
How is laser technology used?/www.ulsinsc.com