Few-Layer Graphene-Based Saturable Absorbers Employing Mica Dispersant for Fiber Lasers

Few-layer graphene-based saturable absorbers (SAs) employing the novel fluorinated mica clay (mica) dispersant for stable mode-locked fiber lasers (MLFLs) are developed. Optical linear absorbance spectrum of graphene-in-polymer film is observed without absorption peak from 400 to 2000 nm. Optical nonlinearities of 1, 2, and 3 wt% graphene-based SAs are initially screened and optimized to be 3 wt% as the highest modulation depth value of 2.46%. By utilizing the mica dispersant for graphene, the developed SA exhibits a stable MLFL showing a pulse width of 382 fs, a bandwidth of 6.80 nm, and a time-bandwidth product of 0.322 at fundamental soliton-like operation. The use of plate-like mica to uniformly disperse graphene-based SAs is crucial for producing stable, ultrafast, and high-performance MLFLs.