Miniaturized microchip array passive Q-switched solid-state laser

To address the spatial constraints in unmanned aerial vehicle target detection systems, a scheme for a multi-beam scanning passive Q-switched microchip array solid-state laser is proposed. This system utilizes a six-core semiconductor laser array to compactly pump a strip-shaped Nd: YAG/Cr4+:YAG bonded crystal. At a pumping power of 1.6 W per path, it generates six output laser beams with a wavelength of 1064.4 nm, pulse width of 2.4 ns, beam quality of 1.39, peak power of 3.75 kW, and a repetition frequency up to 22 kHz. The entire system's volume is only 2 cmx2 cm x1.5 cm, and achieves simultaneous output of six laser paths. The study investigated the impact mechanism of the initial transmittance of the Q-switching crystal and the reflectivity of the output mirror on the laser pulse repetition frequency and peak power, with a particular focus on the uniformity of the laser output from the pump source cores. The feasibility of using a single laser-bonded crystal to produce multiple narrow pulse laser beams in the nanosecond range was experimentally verified. The research results demonstrate the miniaturized structure's ability to achieve multi-beam emission from a passive Q-switched solid-state laser, providing insights for the miniaturization and integration of laser sources in detection systems.