Introduction:
Laser is the greatest invention which was designed by great people. It is used in many ways.
LASER stands for Light Amplification by Stimulated Emission of Radiation. The laser is a light source that exhibits unique properties and a wide variety of applications. Lasers are used in many of the applications like welding, surveying, medicine, communication, national defense, and as tools in many areas of scientific research. Many types of lasers are commercially available today, varying in size from devices that can rest on a fingertip to those that fill large buildings. All these lasers have certain primary characteristic properties in common.
Main Idea:
A laser is a coherent and highly directional radiation source. A laser consists of at least three components:
A gain medium that can amplify light that passes through it.An energy pump source to create a population inversion in the gain medium.Two mirrors that form a resonator cavity.
The gain medium can be solid, liquid, or gas and the pump source can be an electrical discharge, a display light, or another laser device. The specific components of a laser vary depending on the gain medium and whether the laser is operated continuously (cw) or pulsed.
Laser Applications
The Laser Applications are Medical, Barcode Scanners, Laser printing, CDs and optical discs, communication etc...
Medical Lasers device treatments are used for photocoagulation of the retina to halt retinal hemorrhaging and for the tacking of retinal tears. Higher power lasers are used after cataract surgery if the supportive membrane surrounding the implanted lens becomes milky. Photo disruption of the membrane often can cause it to draw back like a shade, almost instantly restoring vision. A focused laser can act as an extremely sharp scalpel for delicate surgery, cauterizing as it cuts. The cauterizing action is particularly important for surgical procedures in blood-rich tissue such as the liver.
Barcode Scanners Supermarket scanners typically use helium-neon lasers to scan the universal barcodes to identify products. The laser beam bounces off a rotating mirror and scans the code, sending a modulated beam to a light detector and then to a computer which has the product information stored. Semiconductor lasers can also be used for this purpose.
Welding and Cutting the highly collimated beam of a laser device can be further focused to a microscopic dot of extremely high energy density for welding and cutting. The automobile industry makes extensive use of carbon dioxide lasers with powers up to several kilowatts for computer controlled welding on auto assembly lines. Garmire points out an interesting application of CO2 lasers to the welding of stainless steel manages on copper cooking pots. A nearly impossible task for conventional welding because of the great difference in thermal conductivities between stainless steel and copper, it is done so quickly by the laser that the thermal conductivities are irrelevant.
Lasers in Communication the light signals can be modulated with the information to be sent by either light emitting diodes or lasers. Telephone fiber drivers may be solid state lasers the size of a grain of sand and consume a power of only half a mill watt. Yet they can sent 50 million pulses per second into an attached telephone fiber and encode over 600 simultaneous telephone conversations. This is also one of the major inventions in science wonders.
In many of the other Applications the Laser is used. It is a great innovation in the world.
