A narrow-linewidth continuous wave Ho：YALO₃ laser with Fabry–Perot etalons

A narrow linewidth continuous wave Ho:YAP laser with two Fabry–Perot etalons pumped by a Tm:YLF laser is reported. The maximum output power reaches 8.3 W when the incident pump power is 15.8 W, with 52.5% optical-to-optical conversion efficiency and 62.6% slope efficiency. A stable laser output at 2118.1 nm is achieved, with a linewidth less than 0.4 nm (full width at half maximum). The beam quality factor is M²～1.25, measured by the traveling knife-edge method.