Dynamics of the CO₂ Atmospheric Pressure Laser with Transverse Pulse Excitation

Abstract

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.

TEA CO2 Laser Simulator: A software tool to predict the output pulse characteristics of TEA CO2 laser

“…From Fig. 13 it can be seen that the calculated results using this program are in good agreement with the experimental data reported in [5]. …”

“…The interesting feature in this type of lasers resulted from the possibility of producing high output power pulses with high efficiency. The output pulse parameters and their delay time depend on the ratio of gas mixture and pumping rates [5,6].…”

“…In literature, there are several models describing the dynamic emission of TEA CO 2 laser [4,5,7], [8, p. 25] such as four-, five-and six-temperature models.…”

Transverse profile evolution of pulses passing through TEA-CO2 amplifiers

“…2 have been drawn from these calculations. Numerical values of the parameters were fixed as follows: rotational amplification cross section o = 10-Is cm2 (7,8), rotational relaxation time z = 0.18 ns (9). Temporal shape of the short pulses was assumed to be Gaussian, with full width at half …”

The transient evolution of AM mode locking a TEA CO2laser

“…We start from a set of rate equations based on a simplified four-level system as previously done by Gilbert et al [8]. It is assumed that the rotational distribution is always ther- malized because of the fast rotational relaxation.…”