Multiple deleterious processes occurring in alkali vapor laser amplifiers can significantly degrade their performance. To study that, a theoretical model of a side-pumped flowing-gas alkali vapor amplifier is set up, which mainly takes into account the effect of saturation, amplified spontaneous emission, quenching, energy pooling, photoexcitation, Penning ionization, photo-ionization, and ion recombination. Influences of powers of the pump and seed laser, the velocity of gas mixture flow, and the cell length on the deleterious processes are also simulated. The results show that the influence of deleterious processes can be increased when pump power enhances. But it can be effectively restrained with relatively strong seed laser power and optimized operating parameters. The total percent drop in amplified laser power is about 19.95% at a pump power of 500 W, a seed laser power of 5 W, a saturated flowing velocity of 40 m/s, and an optimized cell length of 7 cm.

A theoretical model is established to describe the thermal dynamics and laser kinetics in a static pulsed exciplex pumped Cs–Ar laser (XPAL). The temporal behaviors of both the laser output power and temperature rise in XPALs with a long-time pulse and multi-pulse operation modes are calculated and analyzed. In the case of long-time pulse pumping, the results show that the initial laser power increases with a rise in the initial operating temperature, but the laser power decreases quickly due to heat accumulation. In the case of multi-pulse operation, simulation results show that the optimal laser output power can be obtained by appropriately increasing the initial temperature and reducing the thermal relaxation time.

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A theoretical model is established to describe the kinetic processes and laser mechanism for a nanosecond-pulse exciplex pumped Cs vapor laser (XPCsL). A new simulation method is proposed to solve a set of non-stationary rate equations considering high energy levels and the results of simulation are consistent with the experimental data. The effects of cell temperature, pump energy and buffer gas on the output laser pulses are presented and analyzed in detail, which reveal the unique properties of nanosecond-pulse XPCsL.

Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.