Long-time stable Q-switched bulk laser at 1.34 and 1.94 μm based on antimonene saturable absorber

•Successful application of multi-layer antimonene for stable passive Q-switching operations.•Broadband SA properties with a modulation depth of 3.2 % (12.2 %).•Stable Q-switched pulses obtained with pulse duration of 238 ns at 1.94 μm and 324 ns at 1.34 μm.•Long-time pulse duration instability within 180-minute measurement.