1.6-µm Er:YAG Laser with Direct Resonant Laser Diode Pumping

This paper reports the results of what is believed to be the first demonstration of direct diode pumping of the eye-safe Er3+:YAG laser. 1475 nm fibered diode laser modules were implemented to end pump the Er3+(1%):YAG laser rod. The absorbed photon conversion efficiency of 26% has been achieved in these first experiments. Analysis of the DPSSL output characteristics indicates that obtained slope efficiency can be doubled through the intracavity loss reduction and pumping efficiency improvement. Measurements of infrared and green fluorescence intensities clearly indicate that at the excitation levels close to the threshold the upconversion becomes the dominant mechanism limiting the effective lifetime of excited 4I13/2 states.