Modeling of an argon fluoride single pass amplifier*

The US Naval Research Laboratory is developing a repetitively pumped electron-beam ArF* laser based on Electra, which could be the ideal driver for direct and indirect drive for inertial confinement fusion. A kinetics model for the e-beam pumped ArF* laser has been initiated based on the existing Orestes model, initially developed for the KrF* laser at NRL [1]. Uncertainties in many reaction rates and unknown lasing efficiency motivate our basic research program. Here, the existing model was modified to include the Ar-F2 plasma chemistry and rates from a  Boltzmann kinetics model [2]. We report on the results for a single pass amplifier with an external laser source with different intensities. The small signal gain, non-saturable absorption, and saturation intensity of ArF* as a function of applied e-beam power, gas pressure and composition were calculated and compared with the results from experiments. This research enables understanding of power and particle balances, evaluates the extracted laser intensity and intrinsic efficiency as a function of the e-beam power deposition, and further develops the e-beam technologies.

[1] G. M. Petrov, et. al., JAP 91 2662 (2001); 92 1200 (2001).
[2] G. M. Petrov, et. al., JAP 122 133301 (2017).