Pérez García, Victor M.. 

In this paper we analyze the transverse pattern-forming characteristics of a two-level and single-longitudinal-mode laser. The corrections to the classical empty cavity modes due to pumping and losses are specifically considered, leading to different excitation rates for the different transverse modes. The near-threshold excitation rates provide a selection mechanism that is studied and compared to the results from numerical simulations of the Maxwell-Bloch equations.