What are the limitations of rate equations?

The limitations of rate equations are:

  • The rate equations only hold for a laser oscillating with uniform mode and pump energy distribution in the active medium.
  • The rate equations are true for single mode oscillations. For single mode oscillation, we have two equations. For n mode oscillations, we will have 2n differential equations which is very difficult to handle.
  • The rate equations do not apply to an in homogeneously broadened line.