Photonics

Biography

Biography: Guofei An

Abstract

In recent years, a diode-pumped alkali laser (DPAL) has provided the significant promise for high-powered applications. A series of models have been established to analyze the DPAL’s kinetic process and most of them were based on the algorithms in which only the ideal 3-level system was considered. However, alkalis are the most easily ionized atomic species, especially for Rb and Cs. under the condition of strong pumping the electrons will be excited to the higher levels, 62D5/2,3/2 and 82S1/2, by energy pooling collisions. Then, further ionization processes including photo-ionization and Penning ionization will occur on the 62D5/2,3/2 and 82S1/2 levels resulting in decrease of the density of neutral atoms. To examine the kinetic processes of the gas-state media, a mathematical model is developed taking into account the process of normal transition, energy pooling, and ionization. The procedures of heat transfer and laser kinetics were combined together in our theoretical model. We systemically investigated the influences of the temperature, cell length, and cell radius on the output features of a DPAL. By optimizing these key factors, the optical-to-optical conversion efficiency of a DPAL can be evidently improved. Further, the calculated results indicate that the influence of energy pooling and ionization can be obviously suppressed with the optimal parameters. In the case of high pump power, 1000 W, the influence of energy pooling and ionization on output power decreases from 6.02% to 1.04% and the optical-to-optical efficiency increases from 16.5% to 51.5% after optimizing. Basically, some conclusions we obtained here can be extended to any other kinds of end-pumped laser configurations.