Chemical vapor deposition synthesized monolayer MoS₂ for Q-switching pulse generation in the 2 µm spectral region

Abstract

We demonstrate a monolayer MoS2-based saturable absorber (SA) synthesized by chemical vapor deposition (CVD). The as-grown SA has high spatial homogeneity and shows excellent saturable absorption properties in the 2 µm wavelength region. A higher modulation depth of 21.3% and lower saturation intensity of 0.47 MW/cm2 are achieved compared with those of other documented MoS2 SAs to date. When applying the MoS2 SA to a Tm:YAG ceramic laser, we observe a Q-switched pulse train with a shortest pulse duration of 388.0 ns under a pulse repetition rate of 82 kHz, which corresponds to a single pulse energy of 5.4 uJ and a peak power of 14 W. We believe that CVD constitutes an effective method towards high-quality MoS2 saturable absorbers that possess remarkable application potential in the 2 µm wavelength region.

Progress and development on the synthesis and application of two-dimensional molybdenum disulphide

“…A carrier gas like argon and nitrogen are used in order to carry the precursors and to facilitate the mixing of Mo and S in the gas phase. 91 The decomposed (vapour phase) precursors are transported using a carrier gas like argon and nitrogen downstream to substrates for nucleation of MoS 2. 70…”

“…Figure 5. Chemical vapour deposition synthesis of MoS 2 ; thermal decomposition process of precursors (S and MoO 3 ) and nucleation of MoS 2 on substrate using a quartz tube (a)91 and general synthesis procedure of MoS 2 (b) 92. …”