Fig. 1. Theoretical band structure of monolayer ReS2. (a) R=1∶2.057, (b) R=1∶2, (c) R=1∶1.972, (d) R=1∶1.944, and (e) R=1∶1.889.

Fig. 2. Measured position and the corresponding EDS image of (a) the raw bulk ReS2 and (b) the as-prepared few-layered ReS2.

Fig. 3. (a), (b) AFM image of the ReS2 SA with 30  μm×30  μm area and the corresponding distribution of flake thicknesses. (c), (d) High-resolution AFM image with 6  μm×6  μm area and the typical height profiles.

Fig. 4. (a) Raman spectra of the ReS2 SA and the sapphire substrate. (b) Absorption spectra of the ReS2 SA and the sapphire substrate, respectively. (c)–(e) Open aperture Z-scan curves of the ReS2 SA at 0.73, 1.06 and 1.94 μm, respectively.

Fig. 5. ReS2Q-switched laser characteristics. (a)–(c) Average output power and peak power versus the absorbed pump power at 0.64, 1.064, and 1.991 μm, respectively. (d)–(f) Pulse duration and repetition rate versus the absorbed pump power at 0.64, 1.064, and 1.991 μm, respectively.

Fig. 6. (a)–(c) Recorded pulses trains of the ReS2-based Q-switched lasers at 0.64, 1.064, and 1.991 μm, respectively. (d)–(f) Measured output spectra of the ReS2-based Q-switched lasers at 0.64, 1.064, and 1.991 μm, respectively.

Fig. 7. Experimental setup of the ReS2-based mode-locked laser.

Fig. 8. (a) Average output power versus the absorbed pump power of the ReS2-based mode-locked laser. (b) Recorded CWML pulse trains under the maximum pump power.

Fig. 9. Recorded results of ReS2-based mode-locked laser. (a), (b) Autocorrelation trace for 323 fs duration and the corresponding spectrum. (c), (d) Recorded frequency spectrum with a narrow and a wide span, respectively.