Laser
Content
LASER – Acronym stands for Light Amplification by Stimulated Emission of Radiation. Types of LASERS – 3 fundamental types depending upon the lasing medium – 1. Solid lasers 2. Gas lasers 3. Liquid lasers
1. Solid lasers – Eg. Nd-YAG (neodymium-doped-yttrium aluminium garnet)laser – • • • • Crystal used as lasing medium. Wavelength of light produced 1064nm (near infra-red region) Good tissue penetration (not absorbed by water) Uses – Endoscopic surgery – eg. ENT surgery – needs to be handled very carefully due to potential excessive tissue penetration resulting in damage.
2. Gas lasers – a. Carbon dioxide laser – • • • • Highest power laser – also used in industry. Wavelenght of light – 10.6 micrometers (infrared region) Poor tissue penetration < 200 micrometers as absorbed by water causing vaporisation and tissue destruction. Uses – superficial surgery, not suitable for endoscopic surgery.
b. Argon laser – • • • Wavelenght of light between 400 and 700 nm (blue-green region) Good penetration through transparent tissues (components of eye). Maximally absorbed by red-pigmented tissues (as it reflects/emits blue-green light)
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Uses – Eye surgery, dermatological procedures, skin lesions.
3. Liquid lasers – • • • Organic dye used in this type. Wavelenght of light produced is broad and depends on the dye used. Used to even out skin tone.
Classification of lasers – Class 1 – power does not exceed maximum permissible exposure to the eye. Class 2 – power upto 1 mW and visible beams only. Eye protected by blink reflex. Class 3a – power upto 5 mW and visible spectrum only
1. Solid lasers – Eg. Nd-YAG (neodymium-doped-yttrium aluminium garnet)laser – • • • • Crystal used as lasing medium. Wavelength of light produced 1064nm (near infra-red region) Good tissue penetration (not absorbed by water) Uses – Endoscopic surgery – eg. ENT surgery – needs to be handled very carefully due to potential excessive tissue penetration resulting in damage.
2. Gas lasers – a. Carbon dioxide laser – • • • • Highest power laser – also used in industry. Wavelenght of light – 10.6 micrometers (infrared region) Poor tissue penetration < 200 micrometers as absorbed by water causing vaporisation and tissue destruction. Uses – superficial surgery, not suitable for endoscopic surgery.
b. Argon laser – • • • Wavelenght of light between 400 and 700 nm (blue-green region) Good penetration through transparent tissues (components of eye). Maximally absorbed by red-pigmented tissues (as it reflects/emits blue-green light)
•
Uses – Eye surgery, dermatological procedures, skin lesions.
3. Liquid lasers – • • • Organic dye used in this type. Wavelenght of light produced is broad and depends on the dye used. Used to even out skin tone.
Classification of lasers – Class 1 – power does not exceed maximum permissible exposure to the eye. Class 2 – power upto 1 mW and visible beams only. Eye protected by blink reflex. Class 3a – power upto 5 mW and visible spectrum only
