what does laser stand for?
describe its four different applications clearly stating their principles.
2003 question 15


seniors answer please.......

LASER stands for 'Light Amplification by Stimulated Emission of Radiation'.


Laser - A Solution Waiting for a Problem

No one knew what laser would be used for when it was discovered. "A solution waiting for a problem," is a famous saying from the early days of laser. Sometimes it takes quite a long time before a discovery can be used in a tangible way. Yes, it might take 30 years or more before someone realizes that a discovery is really important. Today, laser is used in several areas, such as research, communication, industry, medicine, and environmental care.

Applications of Laser

Industrial Applications of Laser

Today, laser can be found in a broad range of applications within industry, where it can be used for such things as pointing and measuring. In the manufacturing industry, laser is used to measure the ball cylindricity in bearings by observing the dispersion of a laser beam when reflected on the ball.

Yet another example is to measure the shadow of a steel band with the help of a laser light to find out the thickness of the band.

Within the pulp mill industry the concentration of lye is measured by observing how the laser beam refracts in it.

Laser also works as a spirit level and can be used to indicate a flat surface by just sweeping the laser beam along the surface. This is, for instance, used when making walls at building sites. In the mining industry, laser is used to point out the drilling direction.

Environmental Applications

Laser technologies have also been used within environmental areas. One example is the ability to determine from a distance the environmental toxins in a column of smoke. Other examples are being able to predict and measure the existence of photochemical smog and ozone, both at ground level where it isn't wanted and in the upper layers of the atmosphere where it is needed. Laser is also used to supervise wastewater purification.

Communications

Laser works as a light source in all fiber optics in use. It has greater bandwidth (potentially 100,000 times greater) than an ordinary copper cable.
It is insensitive to interference from external electrical and magnetic fields. Crosstalk (hearing someone else's phone call) is of rare occurrence.

Fiber optics is used increasingly often in data and telecommunications around the world.

Research

Laser has become one of the most important tools to researchers within physics, chemistry, biology and medicine throughout the world and is used to:
- register ultra fast chemical processes such as the bonding between atoms to form molecules;
- study the process when cells split, or a virus enters into a cell;
- manipulate molecules down to extremely low temperatures;
- transfer as much energy as possible to different materials in a short time to obtain different types of emissions.

The full meaning of this research won't find its answer today but will be shown in the future.

Medicine

Laser is used in medicine to improve precision work like surgery. Brain surgery is an example of precision surgery that calls for the surgeon to reach the intended area precisely. To make sure of this, lasers are used both to measure and to point in the area in question. Birthmarks, warts and discoloring of the skin can easily be removed with an unfocused laser. The operations are quick and heal quickly and, best of all, they are less painful than ordinary surgery performed with a scalpel.

Entertainment

Laser shows are quite popular and the special effects are amazing. These use lasers that are in the visible spectrum along with vibrating mirrors to paint images in the air. Here is an example of a dance with lasers in the background:

Computers and Music

One popular use of lasers is the reading of CD. CD's function by having a reflective aluminum layer that has very small pits put in the aluminum. The pits and the lack of are translated into binary by the computer and then are used for information. Another use of lasers is in the use of fiber optics. Since lasers travel very fast they make an ideal way to communicate. The laser is shot down a fiberglass tube to a receiver. These wires can be very long with no loss of signal quality. Also modern multiplexing of the line lets two lasers of different frequencies share the same line.

Metal working

Lasers very accurate point and solid state construction make it ideal or industrial production. Lasers allow better cuts on metals and the welding of dissimilar metals with out the use of a flux. Also lasers can be mounted on robotic arms and used in factors. This is safer then oxygen and acetylene, or arc welding.

Some other Applications

Welding and Cutting

Surveying

Garment industry

Laser nuclear fusion

Laser printing

CDs and optical discs

Spectroscopy

Heat treatment

Barcode scanners

Laser cooling

Photochemistry

Microscopy

Military Uses

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Best end of life is not knowledge but action.
Don't limit yourself to what you think people are expecting!

Holography is also application that nneds spcial mention. Anyhow ver good effort

Can anybody differentiate exactly between photoelectric cell and photovoltaic cell?

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“A Momin does not taunt, does not curse and reproach, does not indulge in obscene talking and obscene acts.” [Tirmidhi]

photo electric and photovoltic cell both are almost same and name of solar cell which convert light into DC current