CO2 Laser – Principle, Construction And Working

In a molecular gas laser, laser action is achieved by transitions between vibrational and rotational levels of molecules. Its construction is simple and the output of this laser is continuous.In the CO2 molecular gas laser, transition takes place between the vibrational states of Carbon dioxide molecules.

CO2 Molecular gas laser

CO2 laser was the first molecular gas laser developed by Indian born American scientist Prof.C.K.N.Pillai.It is a four level laser and it operates at 10.6 μm in the far IR region. It is a very efficient laser.

Working Principle Of CO2 Laser:

The active medium is a gas mixture of CO2, N2 and He. The laser transition takes place between the vibrational states of CO2molecules.

co2 laser


It consists of a quartz tube 5 m long and 2.5 cm in the diameter. This discharge tube is filled with gaseous mixture of CO2(active medium), helium and nitrogen with suitable partial pressures.The terminals of the discharge tubes are connected to a D.C power supply. The ends of the discharge tube are fitted with NaCl Brewster windows so that the laser light generated will be polarized.

Two concave mirrors one fully reflecting and the other partially form an optical resonator.

Working Of CO2 Laser-

Add Comment