Lasers Essay, Research Paper

When most

people see a laser beam they are amazed by its

unique physical properties. Laser light is so unique

from other light because it is coherent; unlike

ordinary light, which travels in all directions, laser

light travels in a straight beam. The word laser is

an acronym for Light Amplification by Stimulated

Emission of Radiation. The history of the laser is

very interesting. Lasers have changed immensely

since they were first invented. Before the laser was

invented, Charles Townes developed the maser in

1954. The maser has basically the same principles

as the laser, but it involves microwaves instead of

light. The maser lead Theodore Maximan to

assemble the first working laser in 1960; he did

this by applying the masers qualities to light. This

first solid-state laser was a ruby crystal laser. A

year after the first solid-state laser was invented,

the first gas laser was constructed by Ali Javan,

W. R. Bennett, and D. R. Herriot. This was a

helium-neon laser. The helium-neon laser is the

most common laser found today. Many other

types of lasers have been invented since then: the

semiconductor laser (1962), the chemical laser

(1964), the liquid laser (1966), and the free

electron laser (1977). All lasers work basically on

the same principles. First the atoms in the

substance used are pumped. For example, the

helium and neon would be pumped in a

helium-neon laser. This is where the electrons of

the atoms jump to higher orbitals, which have

more energy. The substance can be pumped by

using flashlamps, other lasers, atomic explosions,

electric discharges, solar energy, and etc… When

the atoms are pumped, they perform stimulated

emission. This is where the electrons are

stimulated by photons to release coherent photons

of a single frequency and color. After the pumping

process, the oscillation process takes place. In this

process energy is amplified to make it stronger

and more useful. This is done by bouncing the

photons between two mirrors until they reach a

certain intensity. The two mirrors are one of 100

percent efficiency and one of a lesser efficiency.

When the photons reach the certain intensity, they

leave the mirror of lesser efficiency in a coherent

beam. There are basically four main types of

lasers: solid-state, gas, liquid, and semi-conductor.

Solid-state lasers are made from a crystalline

material such as ruby. The crystals have impurities

in them that can be stimulated to release radiation

in a coherent fashion. These impurities are needed

to make the laser last for long periods of time. If

the crystals do not have impurities, then they can

have some added; this is called "doping." The

crystals in solid state lasers are usually pumped by

using flashlamps. Gas laser beams are much more

coherent than the beams of solid-state lasers. Gas

lasers are lasers that contain a tube of gas or a

mixture of gasses. The most common gas laser is

the helium-neon laser. Unlike solid-state lasers,

gas lasers are pumped by using electrical

discharges. Liquid lasers are usually filled with an

organic dye substance. These lasers allow

measurements to be taken on a scale never

thought possible. They can do this because they

can be flashed in pulses lasting only billionths of a

second. Liquid lasers are pumped in a very unique

way; they are pumped by using other lasers. The

ruby laser is the most commonly used for this

process. The semiconductor laser is the most

advanced of the four main types of lasers. These

lasers are able to be made smaller than any other

type of laser. This is because the semiconducting

substance used can be smaller than a grain of salt.

The most common semiconductor used in these

lasers is gallium arsenide. This type of laser is the

kind that is used for fiber optic communications.

Because there are so many types of lasers, they

can be used to do a variety of things. One thing

they can be used for is the measurement of

distance and motion. Lasers are great for this

because their frequencies are very sensitive to

motion; they can sense even the smallest of

movements. Lasers can be used for measurement

by comparing their wavelengths with a specific unit

of measurement. There are devices that can

measure the number of wavelengths in a desired

area, so they can be converted into a different unit.

Lasers are great for the measurement of optical

components such as lenses and prisms. Lasers are

also used a lot in industry. Cutting is one of the

applications of lasers in industry. Laser beams can

be focused into a very small spot that is of high

power. The laser can then be used to cut materials

that are to small, hard, or thick to be cut in any

other way; the cuts are also very accurate. Laser

are also used in industry during constructions and

land surveys. For example, lasers were used in the

construction of the Bay Area Transit System; they

used them to make precise alignments of materials.

Land surveyors use lasers to observe the

movements of the fault lines after earthquakes.

Lasers are also used in scientific research.

Scientists have used lasers to calculate the speed

of light to more accuracy than ever before

possible. Lasers are also used in chemistry. For

example, individual chemical reactions can be

induced without inducing others. Also, lasers can

be used to detect and measure things of trace

amounts in substances. Communication is another

thing that lasers are used for. Lasers are great for

this because they are able to travel large distances

without any reduction in quality. This makes lasers

great for communications from earth to space

during space flights; the atmosphere usually

interferes with other forms of communication.

Fiber optic cables are used for communications in

most everyone’s telephone calls or computers.

These cables are able to trap laser light so it can

be directed where ever the cable goes. Lasers are

also used in recording sounds and videos.

Compact disc players and videodisc player are

examples of this. The medical field also make use

of the lasers wide range of capabilities. Laser are

mostly used in making precise cuts and holes

during surgery. Cancerous tumors can also be

removed with the use of lasers. The area of

medicine that the laser is used the most in is eye

surgery. Lasers are used to reattach retinas, and

even to improve vision to make glasses obsolete.

Lasers also play a big part in the military. Lasers

can be found on almost all military airplanes and

missiles. The laser provide them with the most

advanced guidance systems available. Laser may

also be used the shoot down missiles that are in

danger of hitting critical areas. President Reagan

suggested that these lasers be mounted on

satellites in space to prevent missile attacks on the

United States; this was nicknamed "star wars."

Lasers are also used on some of the militaries guns

as advanced aiming devices. As you see, lasers

have come along way since the first one was

invented. They come in a variety of different

forms. Because of the wide variety of lasers, they

can be used for many different functions. They can

be used in industry, medicine, communication,

science, military, and much more. Lasers have

played a big part in today’s technology.

BIBLOGRAPHY "Laser." Funk and Wagnall’s

Encyclopedia. Copyright 1994 by Funk and

Wagnalls, Corp. Maurer, Allan. Lasers: Light

Wave of the Future. Arco Publishing. New York,

New York. 1982. pp. 1-166. Lengyel, Bela.

Introduction to Laser Physics. John Wiley and

Sons, Inc. Sydney. 1966. pp. 49-289. Mauldin,

John. Light, Lasers, and Optics. Tab Books, Inc.

Blue Ridge Summit, PA. 1988. pp. 143-158.