Research on active and passive dual-loss Q-switched laser based on the WTe2/MoS2 heterojunction

This paper mainly studies the realization of active and passive dual-loss Q-switched of solid-state lasers based on the WTe₂/MoS₂ heterojunction thin-film material in combination with an acoustic-optic modulator(AOM), thereby optimizing the output characteristics of 1.06μm laser pulses. The WTe₂/MoS₂ heterojunction nanocomposite thin films were prepared using the spin coating method. The saturation absorption characteristics of the material were tested using the power meter scanning method. The WTe2/MoS₂ heterojunction was used as a passive saturable absorber material in an LD-pumped laser to achieve passive Q-switched. When the pump power is 2.3 W, the maximum average output power, pulse width, pulse repetition rate, single pulse energy, and peak power are 768 mW, 279 ns, 324 kHz, 2.37 μJ, and 8.49 W, respectively. By taking advantage of the saturable absorption characteristics of WTe₂/MoS₂, it was inserted into an LD end-pumped Nd³⁺:YVO₄ AOM Q-switched laser to achieve active and passive dual-loss Q-switched operation. The experiments show that compared with AOM active Q-switched, the AOM+WTe₂/MoS₂ active and passive dual-loss Q-switched laser characteristics are optimized. The introduction of WTe₂/MoS₂ as a passive saturable absorber material reduces the threshold of the original AOM active Q-switched laser. When the AOM frequency is 15 kHz, the narrowest pulse width of the dual-loss Q-switched laser is 64 ns, which is 44.3% narrower than that of the single AOM active Q-switched laser; the peak power of the dual-loss modulated laser is 0.62 kW, which is 48.3% higher than that of the single AOM active modulation. The pulse width compression and peak power increase are very obvious, which is beneficial to the instantaneous energy output of the laser.