  We use liquid phase exfoliation to produce dispersions of molybdenum
disulphide (MoS2) nanoflakes in aqueous surfactant solutions. The chemical
structures of the bile salt surfactants play a crucial role in the exfoliation
and stabilization of MoS2. The resultant MoS2 dispersions are heavily enriched
in single and few (<6) layer flakes with large edge to surface area ratio. We
use the dispersions to fabricate free-standing polymer composite wide-band
saturable absorbers to develop mode-locked and Q- switched fibre lasers,
tunable from 1535-1565 and 1030-1070 nm, respectively. We attribute this
sub-bandgap optical absorption and its nonlinear saturation behaviour to
edge-mediated states introduced within the material band-gap of the exfoliated
MoS2 nanoflakes.
