“…Compared with the conventional semiconductor SA mirror and other artificial SAs, − real SAs implemented with layered van der Waals (vdW) materials boast low cost, a compact structure, a simple setup, and an adjustable operating bandwidth. − Currently, various vdW materials have been investigated for ultrafast photonics, including transition-metal dichalcogenides (TMDCs) (i.e., MoS 2 , NbS 2 , Ag 2 S, HfS 2 , WSe 2 ), − topological insulators (TIs) (i.e., Bi 2 Te 3 , Sb 2 Te 3 , Bi 2 Se 3 ), − MXenes (i.e., Ti 3 C 2 T x , Mo 2 C), − black phosphorus, and transition-metal phosphorus trichalcogenides (i.e., FePSe 3 , NiPS 3 , MnPSe 3 ). − Generally speaking, these vdW SA-based pulse generations follow the Fourier transform limitation, essentially stating that the product of temporal uncertainty (or pulse duration) and frequency uncertainty (or bandwidth) is minimized . To obtain an ultrafast pulse, the generation of a wide spectrum is necessary, though chirps often occur because of dispersion, Kerr effect, and some other influences in the practical pulse. − Actually, the majority of vdW material SA-based pulse lasers manifest narrow spectral bandwidth (<10 nm), and the as-generated pulses are commonly limited to picosecond or sub-picosecond. ,,,, Rare vdW material SA-based ultrafast mode-locked lasers delivered a wide 3 dB spectral bandwidth, , which produced femtosecond ultrashort pulses. Consequently, to achieve an ultrashort pulse, it is an ongoing task to search for appropriate vdW material SAs endow ultrafast mode-locked lasers with ultrashort durations and broad spectra.…”