A saturable absorber based on a novel two-dimensional (2D) material Bi 2 O 2 Se was placed in a resonator with an overall longest diameter of 31 mm to achieve efficient operation of a passively Q-switched (PQS) Tm:YAP laser for the first time. In PQS mode, a 1.62-W average output power with a pulse width of 1.24 µs and a pulse repetition of frequency of 112.1 kHz was achieved at the pump power of 22.2 W, corresponding to a peak power of 11.66 W. As a novel 2D material, the results show the potential of Bi 2 O 2 Se as a photomodulator in the 2 µm spectral range.

In this research, a diode-pumped SnS 2 passively Q-switched (PQS) V-type Tm-doped pulsed laser was demonstrated. The continuous-wave (CW) condition without SnS 2 saturable absorber (SA) was investigated first. A maximum output power of 1.26W with a slope efficiency of 24.28% was derived at an absorbed pump power of 7.11W under an output coupling of 5%. With the as-prepared SnS 2 SA employed, a series of stable Q-switched (QS) pulse trains were successfully realized. A minimum pulse width of 3.061 μs and a maximum repetition frequency of 70.42 kHz were generated through an output coupling of 5%, corresponding to a maximum output power of 621 mW. The delivered highest peak power and maximum single pulse energy were 2.90W and 12.41 μJ under an output coupling of 2.5%, respectively. These findings indicated that SnS 2 was a promising modulator for 2 μm all-solid-state pulsed laser generation.

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