Engineering Physics

10.9 Carbon dioxide laser

(i) Introduction: The carbon dioxide laser was invented by C. Kumar. N. Patel in the year 1963. This laser uses a mixture of carbon dioxide [CO₂], Nitrogen [N₂] and Helium [He] gases in the active medium of laser. The lasing action is from carbon dioxide molecules. They are the active molecules in the laser. The CO₂ molecule is a linear symmetric molecule with carbon atom at the centre and oxygen atoms are on each side of the carbon atom. The lasing is due to the transitions of CO₂ molecules in between vibrational-rotational levels. The CO₂ molecules possess three different types of vibrational modes and each vibrational mode possesses a number of rotational modes. The vibrational modes are described as shown in Fig. ...