27-07-2012, 03:00 PM
LASER COMMUNICATION
LASER COMMUNICATION.ppt (Size: 3.18 MB / Downloads: 142)
INTRODUCTION
Invented in 1985 by Charles Townes & Arthur Schawlow of Bell laboratories.
Was based on Einstein idea of the particle – wave duality of light more than 30 yrs earlier.
Originally called as MASER (m=microwave)
LASERS IN COMMUNICATIONS
Fiber optic cables are a major mode of communication partly because multiple signals can be sent with high quality and low loss by light propagating along the fibers.
The light signals can be modulated with the information to be sent by either light emitting diodes or lasers.
The lasers have significant advantages because they are more nearly monochromatic and this allows the pulse shape to be maintained better over long distances.
MEDICAL
Cosmetic surgery (removing tattoos scars, stretch marks, sunspots, wrinkles, birthmarks, and hairs)
Eye surgery and refractive surgery
Soft tissue surgery
Laser scalpel (General surgery, gynecological, urology, laparoscopic)
Dental procedures
Photobiomodulation (i.e. laser therapy)
"No-Touch" removal of tumors, especially of the brain and spinal cord.
In dentistry for caries removal, endodontic/periodontic procedures, tooth whitening, and oral surgery.
WELDING & CUTTING
The highly collimated beam of a laser 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.
LASER IN THE GARMENT INDUSTRY
Laser cutters are credited with keeping the U.S. garment industry competitive in the world market. Computer controlled laser garment cutters can be programmed to cut out 400 size 6 and then 700 size 9 garments - and that might involve just a few cuts. The programmed cutter can cut dozens to hundreds of thicknesses of cloth, and can cut out every piece of the garment in a single run.
The usefulness of the laser for such cutting operations comes from the fact that the beam is highly collimated and can be further focused to a microscopic dot of extremely high energy density for cutting.
HEAT TREATMENT
Heat treatments for hardening or annealing have been long practiced in metallurgy. But lasers offer some new possibilities for selective heat treatments of metal parts. For example, lasers can provide localized heat treatments such as the hardening of the surfaces of automobile camshafts.
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.
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INTRODUCTION
Invented in 1985 by Charles Townes & Arthur Schawlow of Bell laboratories.
Was based on Einstein idea of the particle – wave duality of light more than 30 yrs earlier.
Originally called as MASER (m=microwave)
LASERS IN COMMUNICATIONS
Fiber optic cables are a major mode of communication partly because multiple signals can be sent with high quality and low loss by light propagating along the fibers.
The light signals can be modulated with the information to be sent by either light emitting diodes or lasers.
The lasers have significant advantages because they are more nearly monochromatic and this allows the pulse shape to be maintained better over long distances.
MEDICAL
Cosmetic surgery (removing tattoos scars, stretch marks, sunspots, wrinkles, birthmarks, and hairs)
Eye surgery and refractive surgery
Soft tissue surgery
Laser scalpel (General surgery, gynecological, urology, laparoscopic)
Dental procedures
Photobiomodulation (i.e. laser therapy)
"No-Touch" removal of tumors, especially of the brain and spinal cord.
In dentistry for caries removal, endodontic/periodontic procedures, tooth whitening, and oral surgery.
WELDING & CUTTING
The highly collimated beam of a laser 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.
LASER IN THE GARMENT INDUSTRY
Laser cutters are credited with keeping the U.S. garment industry competitive in the world market. Computer controlled laser garment cutters can be programmed to cut out 400 size 6 and then 700 size 9 garments - and that might involve just a few cuts. The programmed cutter can cut dozens to hundreds of thicknesses of cloth, and can cut out every piece of the garment in a single run.
The usefulness of the laser for such cutting operations comes from the fact that the beam is highly collimated and can be further focused to a microscopic dot of extremely high energy density for cutting.
HEAT TREATMENT
Heat treatments for hardening or annealing have been long practiced in metallurgy. But lasers offer some new possibilities for selective heat treatments of metal parts. For example, lasers can provide localized heat treatments such as the hardening of the surfaces of automobile camshafts.
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.