Development of high energy laser analysis software along with experimental verification of DPAL rate constants

Under the work proposed here, we will develop a physics based comprehensive software for modeling the behavior of a diode pumped alkali laser: DPAL. The software will be designed primarily for a He-Rb DPAL. However, it could easily be applied to DPALs based on other alkali atoms, such as Cs. Furthermore, the model would be versatile enough to be applicable to other high energy lasers as well. Contrary to the conventional rate equation approach, which is often inadequate in predicting effects such as frequency pulling and spectral properties, we will make use of a comprehensive approach based on density matrix. We will also model the pump using a stochastic phase diffusion model, which is likely to be more accurate than the conventional approach of using spectrally inhomogeneous absorption cross sections. We will also employ computational fluid dynamics techniques to take into account the effect of fluid flow and temperature gradients. Longitudinal and transversal intensity variations will also be treated carefully. Northwestern University (NU), with Prof. Selim Shahriar as PI, will serve as a subcontractor, and will contribute to the development of the theoretical model. Both NU and DOT (the prime) have several DPALs currently operating. These DPALs will be used to carry out experimental verification of the relevant DPAL rate constants. Prof. Yuri Rostovtsev of University of North Texas, an expert in all theoretical aspects of this project, will work as a consultant to DOT, and will be the leader of the theoretical effort.