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CO2 Laser - Another Form of Laser Technique

LASER is an abbreviated form light amplification by stimulated emission of radiation. Lasers are highly coherent source of light which carry high energy. This source of light is obtained by stimulated emission whereas in light emitting device it is spontaneous emission. The main advantage of stimulated emission is that these light rays are coherent of same frequency and have the same phase. Hence Laser lights diverges less and a beam of laser is highly concentrated and have a great directional property.

Lasers have basically three functional steps, the first being pumping. During pumping, the electrons in the ground state are energized and are made to move to a higher level. Now while in excited these electrons try to get back to their normal ground state.  But in a laser there is another state that lies between the excited state and the ground state. This state is the Meta stable state as it lies between the excited state and the ground state.

When the electrons in the excited state move down to the Meta stable state they emit energy in the form of photons. These photons are then absorbed by the electrons in the ground state. Hence the electrons in the ground state are exited to the excited state.

Under normal condition the number of molecules in the excited state is much less than those in the ground state. But due to pumping and gradual shift from excited state to Meta stable state, the concentration of molecules in the metastable state increase beyond the molecules in the ground state. This condition where the number of molecules in the excited state (Meta stable) state is more than the electrons in the ground state is known as population inversion. Population inversion is the main reason for the stimulated emission in the lasers.

When these molecules in the Meta stable state move to the ground state they tend to release energy in the form of photons, which lie in the visible spectra of light. Since the transition is from the fixed Meta stable state to the fixed ground state the light emitted is of the same frequency and same wavelength.

CO2 Lasers are among the first lasers that were developed. Rather these were the first lasers which employed a gas that is carbon di oxide for the purpose of obtaining the laser light. This type of gas laser was developed by an Indian Scientist, Kumar Patel. Kumar Patel invented the gas lasers and he did his research work in the Bell Laboratories.

Carbon di oxide lasers or simply Co2 lasers are one of the most powerful lasers and they have found their application in a large number places.

Carbon di oxide lasers are among the most powerful lasers that provide a continuous wavelength light beam. Although these were among the first lasers that were invented they are still in use and are still available. It has been found that the efficiency of the lasers, which employ the carbon di oxide gas, has high efficiency and is known to provide a pumping efficiency of about twenty percent.