Rate Equation Analysis of Flowing Lasing Systems Part I. Uniform Pumping

A simple analytical model for flowing laser systems has been developed. The lasing species is modeled as a two-state system with specified pumping and relaxation rates. Threshold requirements and output efficiency are expressed in the form of universal dimensionless functions. In terms of these universal functions, the behavior of particular systems can be studied in a parametric way. The analysis shows that flow would not improve the performance of all laser systems. The transformation ∂/∂t → v ∂/∂x allows one to predict the performance of flowing systems from the behavior of pulsed systems.