The depopulation of the ground state for population inversion is achieved by exciting the atoms of the ruby crystal with intense light from a xenon flash lamp. Thus the atoms are excited from the ground state (level 1) to an upper state (level 3) by means of absorption. From the energy level 3, the atoms are transferred to energy level 2 without emitting radiation (non-radiative transfer). The energy level 2 is called met stable level since the atoms stay at this level for a longer interval of time. Finally, the atoms return to the ground state from the met stable level through the process of stimulated emission giving rise to an intense laser light at 6943A. The laser beam comes out in the form of a pulse of very short duration (about a millisecond). The continuous wave operation of the system is very difficult to achieve. Only 1 to 2 per cent of the input is utilized to obtain the laser action. The rest is dissipated