Rhenium disulfide-based passively Q-switched dual-wavelength laser at 0.95 μm and 1.06 μm in Nd:YAG

We demonstrate a passively Q-switched dual-wavelength (0.95 μm, 1.06 μm) neodymium-doped laser based on a few-layer rhenium disulfide (ReS₂) saturable absorber (SA). By a liquid exfoliation method, few-layer ReS₂ was prepared, and then its nonlinear optical response was examined by an open aperture Z-scan method. By using a ReS₂ SA, a 0.95, 1.06 μm dual-wavelength pulsed solid state laser with a mode waist controllable linear multi-mirror cavity has been reported for the first time. The ReS₂ SA Q-switched dual-wavelength oscillation threshold was recorded to be 1.35 W. At the absorbed pump power of 3.07 W, a maximum average output power of 81 mW was obtained, corresponding to the shortest pulse width of 834 ns and a repetition frequency of 165 kHz. This is, to our knowledge, the first assessment of saturable absorption and dual-wavelength Q-switching ability adjacent to the bandgap of ReS₂. The result indicates that few-layered ReS₂ SAs are good candidates for 0.95, 1.06 μm simultaneous pulsed laser oscillating systems. (letter)