Fig. 1. (a) TEM image of TiCN; (b) Lattice fringes of TiCN under an HRTEM

Fig. 2. Experimental setup of the passively QSML Er³⁺-doped fluoride fiber laser using TiCN as the saturable absorber

Fig. 3. Oscilloscope traces of the QSML pulse trains measured under different pump power. (a) Pump power of 320 mW; (b) Pump power of 330 mW; (c) Pump power of 420 mW; (d) Pump power of 500 mW

Fig. 4. (a) The repetition frequency and pulse duration of QSML pulse envelope as a function of pump power; (b) The average output power as a function of pump power

Fig. 5. (a-b) Oscilloscope traces of the mode-locked pulse trains under different pump power; (c) The spectrum of the QSML pulses under the pump power of 500 mW; (c) The radio-frequency spectrum of the QSML pulses under the pump power of 500 mW