Based on the rate-equations of quasi-three-level lasers, we analyzed the threshold and the output power of longitudinally pumped Tm:YAG lasers in an active mirror configuration. In contrast to one-pass pumping, two-pass pumping in this configuration will result in a 24% decrease in threshold and 16% increase in slope efficiency. Using a 3-W diode-laser pumping in the active mirror configuration, we demonstrated a CW Tm:YAG laser and obtained 735 mW output power with a slope efficiency up to 49%. Using a Ti:sapphire laser to pump the same device, the threshold power was further reduced and the slope efficiency reached 59%.
solid-state lasers Tm:YAG laser diode-pumped lasers active mirror