Surfactant-aided exfoliation of molydenum disulphide for ultrafast pulse generation through edge-state saturable absorption

TL;DR

This paper demonstrates the use of surfactant-assisted liquid phase exfoliation to produce MoS2 nanoflakes for ultrafast laser pulse generation, highlighting edge-state saturable absorption as the key mechanism.

Contribution

It introduces a method to produce high-quality MoS2 nanoflakes with edge states for efficient saturable absorption in fiber lasers.

Findings

Successful exfoliation of MoS2 into few-layer flakes

Effective fabrication of polymer composite saturable absorbers

Achieved tunable mode-locked and Q-switched fiber lasers

Abstract

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.