Solution-processed antimonene integrated arc-shaped fiber for mode-locked pulse laser generation at 1.9 μm spectral region

A mono-element 2D material named antimonene has more favorable physical and optical characteristics than its bulk counterpart, making it an excellent saturable absorber (SA) material. Few layers of 2D antimonene solution were synthesized using the ultrasonic-assisted liquid-phase exfoliation (LPE) approach. The nonlinear absorption properties were measured using a balanced twin detection method, with saturable absorption of 9.6% and saturation intensity of 0.11 MW/cm(2). The drop-casting technique incorporated a few drops of 2D antimonene solution onto the fabricated arc-shaped fiber. The laser performances were observed upon integrating the antimonene/arc-shaped fiber-based SA into the thulium/holmium-doped fiber (THDF) laser cavity. A soliton optical spectrum was produced at the pump power of 292.7 mW with a central wavelength of 1914.95 nm and 3-dB bandwidth of 2.41 nm. In addition, stable mode-locked pulses were produced with a frequency of 11.1 MHz and pulse width of 1.61 ps. The high stability of generated pulses was evidenced by the high signal-to-noise ratio of 62.7 dB and no significant fluctuation on central wavelength and 3 dB bandwidth throughout the 3 h of the observation period. These findings imply the potential of 2D antimonene in developing desired photonic applications, particularly in broadband ultrafast photonics.