Study on a gas flowing diode pumped cesium laser

Abstract

Because of the low thermal conductivity of the mixture gases in an alkali vapor cell, the temperature of the pumping area of an alkali vapor cell can be extremely high than that of other area. Therefore, thermally-induced effects, such as, consumption of atomic alkali, degradation of output power, glass window contamination by the products of the optically chemical reaction between atomic alkali and buffer gases, etc. can be observed in high temperature heated diode pumped alkali lasers (DPALs) in the case of high power pumping. Generally, a flowing diode pumped alkali laser (FDPAL) system is thought to be a useful way to mitigate thermal effects in a DPAL system. In the paper, a mathematical model of a flowing diode pumped cesium laser (FDPCL) was constructed to systematically study the temperature distribution, the flow filed distribution, and the impacts of pressure of the buffer gases on output power of a FDPCL, etc. The laser kinetics, heat transfer, and computational fluid dynamics (CFD) are both taken into account at the same time during the simulation. The multi-physics coupling method was utilized to solve such three physics induced problem during the simulation. It has been demonstrated that the temperature distribution of a FDPCL system depends on the distribution of gas flow filed, a gas flow method can decrease thermal effects in a DPAL system, and the output power of a DPAL can be improved by increasing the velocity of gas flow filed.