Dynamics of the CO2 Atmospheric Pressure Laser with Transverse Pulse Excitation

The dynamical processes responsible for laser emission in the pulsed pumping of a transversely excited atmospheric (TEA) CO2 laser are investigated. An explanation for the formation of the giant pulse is proposed on the basis of a gain-switching mechanism in which it is assumed that with short strong-current pulses a high population inversion can be achieved prior to the onset of laser action. The kinetics of the mechanism are described by means of a set of nonlinear rate equations idealized to a four-energy-state system. With suitable initial conditions on the populations, the transient solution of these equations for the mixtures CO2–He and CO–N2–He appears to be consistent with the major features of experimental observation.