Effect of Iron and Copper Impurity Ions on Laser Efficiency of Phosphate Laser Glass

The effect of impurity such as Fe and Cu ions on the optical loss and laser performance of N31-type Nd-doped phosphate laser glass was studied. It was found that the laser slope efficiency decreased in accordance with an e exponential function, and the laser threshold increased in quadratic with the increase of Fe concentration. Moreover, the empirical equations between concentration of Fe with laser slope efficiency and laser threshold were obtained. It also showed that laser efficiency was seriously influenced by Cu ion compared with that by Fe ion at the same concentration. The results are useful for improving the gain performance of laser glass and quantitatively control of the impurity in raw materials in the future.