Antimonene based saturable absorber for soliton mode-locked and Q-switched fiber laser at 2 μm wavelength region

Abstract

Abstract In this work, we have demonstrated antimonene as a saturable absorber to generate ultrafast mode-locked and Q-switched laser at a 2-micron wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium-holmium doped fiber laser (THDFL) to produce the pulsed lasers. Antimonene was coated onto the tapered fiber to generate soliton mode-locked pulses and in thin-film form for the generation of Q-switched pulses. The modelocking was stable within the pump power of 267 to 511 mW, and the laser operated at the center wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 MHz, with a signal-to-noise ratio (SNR) of 64 dB. The Q-switched laser operation was stable at the wavelength of 1890.1 nm within the pump power of 312 to 381 mW. With the increase in pump power from 312 mW to 381 mW, the repetition rate increased to a maximum of 56.63 kHz and the pulse width decreased to a minimum value of 2.85 μs. A wide range tunability of Q-switched laser was also realized within the wavelength of 1882 to 1936 nm.