If in a three-level laser system. Assume cw laser action takes place on the 3 to 2 rather than the 2 to 1 transition. Suppose level 3 in such a system is long-lived with lifetime t3, level 2 has a short relaxation time to the ground state. and the system is pumped with transition probability Wp on the 1 to 3 transition. Comparing with?n versus Wp for this system.

le8 Population Inversion vs. Pumping Rate 1.0 0.8 0.6 Population Inversion (An) 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Pumping Rate (W/m* 3) le17