MXene Ti3C2Tx-ZnO heterostructure for Q-switched and mode-locked fiber laser at 1.5 µm

This work demonstrates a saturable absorber (SA) based on Ti 3 C 2 T x -zinc oxide (ZnO), for Q-switched and mode-locked generation in an erbium-doped fiber laser (EDFL) cavity. The SA was fabricated using a solution-casting method, in which both materials were mixed to form a thin-film structure. The UV–vis-NIR spectroscopy and twin-balanced detector technique reveal a 0.4 a.u. absorbance and 10.1% modulation depth, indicating its potential as SA. The film was incorporated in the EDFL cavity, initiating a Q-switched and mode-locked laser in the 1.5 µm regime. The Ti 3 C 2 T x -ZnO generates Q-switched pulses at a center wavelength of 1559.8 nm, and the center wavelength blue-shifts to 1558.65 nm when the laser operates in the mode-locking regime. The minimum pulse width of the Q-switched and mode-locked pulses is 6.56 µs and 3.91 ps, respectively. The developed SA can also be used for pulsed laser generation in another near-to-mid-infrared regime, including 1-, 1.33–, and 2-µm.