Abstract
ReS2 films with different thickness are fabricated by a vacuum filtration from liquid exfoliated ReS 2 suspension. The saturable absorption properties of these films are investigated by an open-aperture Z-scan technique with a femtosecond laser. The saturable absorption coefficients ${{{\alpha }}_{{\rm{NL}}}}$ and the imaginary part of the third-order optical susceptibility ${\rm{Im}}{{{\chi }}^{(3)}}$ are from −61.5 to −171.8 cm/GW and from $- {\text{2.24}}\times {\text{10}}^{- 11}$ to $- {\text{6.27}}\times {\text{10}}^{- 11}$ esu with the change of thickness. The figure of merit increases with the increasing of the thickness of ReS2 films, which suggests the possible layer-coupling influence to the nonlinear optical properties. A double-covered ReS2 microfiber as a saturable absorber is then fabricated. We obtain stable mode-locking pulses with high-damage threshold (410 mW), which are centered at 1563.3 nm with the duration of 3.8 ps and the fundamental repetition of 1.78 MHz. Our results provide complementary information for the reliable ReS2 film fabrication with good nonlinear optical property for the mode-locking fiber lasers.
Published Version
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