-: CO₂ Laser :-
The CO₂ laser is a four - level molecular gas laser system . It is a very important laser due to its high efficiency and high power continuous wave capacity . Nitrogen and helium gases are used to increase the efficiency of CO₂ gas laser .
Construction :- Carbon Dioxide (CO₂) gas laser consists of a discharge tube of length 25 cm and a diameter of about 2-5 cm . The tube contains mixture of Helium (He) , Nitrogen (N₂) and Carbon Dioxide (CO₂) gases in the ratio of 5:4:1 . The pressure of these gases are 7 torr , 1.2 torr and 0.33 torr for helium , nitrogen and carbon dioxide respectively . Both ends of the tube are sealed by optically plane and parallel mirrors . One end of the mirror is highly silvered whereas the other is partially silvered . Brewster window is used at the end of the tube . Two electrodes are inserted in the tube to give high power to achieve population inversion by electric discharge method . The schematic diagram is given as -
Working :-
A high D.C. voltage causes an electric discharge to pass through the tube . The nitrogen molecules are exited by collisions . Then excited nitrogen molecules flow into the whole volume of resonant cavity and transfer their energy to excite carbon dioxide molecules to a particular vibrational state E₅ .
In CO₂ laser , N₂ plays the same role as He in He-Ne Laser . The helium gas not only helps to populate the upper energy level but also helps to remove population from the lower energy level of carbon dioxide gas molecules . The excited CO₂ gas molecule , in turn ,undergo radiative transition to the lower vibrational energy levels E₄ and E₃ giving rise to lower radiation of wavelength 10.6𝛍𝙢 and 9.6 𝛍𝙢 respectively .
Advantages :-
1- CO₂ has high absorption for common materials .
2- Long Rayleigh length for thicker materials .
3- CO₂ laser is rapidly used in materials processing .
4- Resolution is acceptable with shorter focal length .
5- CO₂ laser is cheaper than other laser for industry .
Disadvantages / Drawbacks of CO₂ Laser :-
1- CO₂ laser has low power density .
2- Different focal length needed for applications .
3- CO₂ laser has larger high voltage tube .
4- CO₂ laser has one mode of operation .
5- CO₂ laser can not process infrared reflecting materials .
Application of CO₂ Laser :-
1- CO₂ gas laser are used in eye and tissue surgery .
2- CO₂ are also used in welding , cutting and heat treatment of materials .
3- CO₂ laser is used in laser fusion and beam weapons .
The CO₂ laser is a four - level molecular gas laser system . It is a very important laser due to its high efficiency and high power continuous wave capacity . Nitrogen and helium gases are used to increase the efficiency of CO₂ gas laser .
Construction :- Carbon Dioxide (CO₂) gas laser consists of a discharge tube of length 25 cm and a diameter of about 2-5 cm . The tube contains mixture of Helium (He) , Nitrogen (N₂) and Carbon Dioxide (CO₂) gases in the ratio of 5:4:1 . The pressure of these gases are 7 torr , 1.2 torr and 0.33 torr for helium , nitrogen and carbon dioxide respectively . Both ends of the tube are sealed by optically plane and parallel mirrors . One end of the mirror is highly silvered whereas the other is partially silvered . Brewster window is used at the end of the tube . Two electrodes are inserted in the tube to give high power to achieve population inversion by electric discharge method . The schematic diagram is given as -
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Working :-
A high D.C. voltage causes an electric discharge to pass through the tube . The nitrogen molecules are exited by collisions . Then excited nitrogen molecules flow into the whole volume of resonant cavity and transfer their energy to excite carbon dioxide molecules to a particular vibrational state E₅ .
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Advantages :-
1- CO₂ has high absorption for common materials .
2- Long Rayleigh length for thicker materials .
3- CO₂ laser is rapidly used in materials processing .
4- Resolution is acceptable with shorter focal length .
5- CO₂ laser is cheaper than other laser for industry .
Disadvantages / Drawbacks of CO₂ Laser :-
1- CO₂ laser has low power density .
2- Different focal length needed for applications .
3- CO₂ laser has larger high voltage tube .
4- CO₂ laser has one mode of operation .
5- CO₂ laser can not process infrared reflecting materials .
Application of CO₂ Laser :-
1- CO₂ gas laser are used in eye and tissue surgery .
2- CO₂ are also used in welding , cutting and heat treatment of materials .
3- CO₂ laser is used in laser fusion and beam weapons .
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