lasers in medicine, basic principles and application
Post on 15-Apr-2017
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LASER PRINCIPLESDr. Prathyusha PG ENTNarayana Medical College, Nellore
DEFINITION It is an intense beam of coherent monochromatic light (or other electromagnetic radiation) by stimulated emission of photons from excited atoms or molecules
light amplification by stimulated emission of radiation.
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CONFUSION????!!!!!!
BEFORE WE GO DEEPEEER
KNOW THESE TERMS…..• Absorption
• Emission
• Population inversion
• Stimulated emission
ABSORPTION AND EMISSION
VIDEO
PRINCIPLES AND WORKING OF A LASER _PART 1 - YouTube (480p).mp4
PRINCIPLES AND WORKING OF A LASER _PART 2 - YouTube (480p).mp4
DIFFERENCE BETWEEN SPONTANEOUS AND STIMULATED EMISSIONS
Spontaneous emission Stimulated emission
Spontaneous process and automatically produced
Induced by external radiation
No need of population inversion Requires population inversion
Photons produced are of different energy levels hence incoherent
Same energy levels hence coherent
Photons emitted travel randomly in any direction
Travels in the same direction as the incident photon
SPECTRUM OF ELECTROMAGNETIC RADIATION
CHARACTERISTICS OF LASER RADIATION - YouTube (480p).mp4
CHARACTERISTICS OF LASER
CHARACTERISTICS OF LASER RADIATION - 2 - YouTube (480p).mp4
EFFECT OF LASER BEAM ON THE TISSUES
ZONES OF TISSUE DESTRUCTION
EFFECTS OF LASER• Photo thermal
• Photo acoustic
• Photochemical
• Photodissociation
INVISIBLE LASERS • UV zone
• Infrared
• Micro infrared
VISIBLE LASERS• Different colours
• Argon blue
• KTP laser blue-green color
OPERATIONAL PARAMETERS• Wave length of the laser
• Power
• Exposure time
• Spot size
• Power density
MODES OF DELIVERY• Continous mode
• Pulsed mode
• Q switched mode
DISADVANTAGES OF LASER• High cost
• Special training
• Hazards
• Special anaesthesia
THANK YOU
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