LD pumped kHz Er³⁺, Yb³⁺: glass passively Q-switched microchip lasers

At present, 1.5 m LD pumped Er-glass passively Q-switched micro-laser is a popular research direction in military laser ranging. Achieving high repetition rate and single pulse energy are very important indicators. In this paper, a kHz erbium-ytterbium co-doped phosphate glass passively Q-switched microchip laser for laser ranging was reported. The laser was pumped by a single diode with a center wavelength of 940 nm and erbium-ytterbium co-doped phosphate glass (Er3+,Yb3+:glass) as the gain medium, CO2+:MgAl2O4 (CO:MALO) as the saturable absorber. By analyzing the influence of the pump spot radius on the mode-matching, the pump spot radius was optimized. The effects of the initial transmittance (T0) of saturable absorber and the reflectance R of output mirror on the output laser parameters were experimentally analyzed. In the final pre-pumping experiment, a Q-switched pulse was achieved, with repetition frequency of 1 kHz, wavelength of 1 535 nm, single pulse energy of 40 J, pulse width of 5.09 ns, peak power of 7.89 kW and beam quality of 1.4.