“…As a result, multi-layer BPs can be obtained using the liquid exfoliation or mechanical cleavage method [ 30 , 31 , 32 , 33 ]. Currently, mechanically cleaved BP, microfiber-based multi-layer BP, and BP polymer composites have been used as SAs to generate Q-switched/mode-locked pulses at 1, 1.55, and 2 μm, respectively [ 21 , 34 , 35 ]. However, in the atmosphere, BP is unstable and tends to be oxidized due to the existence of O 2 or H 2 O [ 36 , 37 , 38 ].…”