Optical nonlinearity of Cu1.81S nanodisks decorated with silver nanoparticles

The nonlinear absorption (NLA) and ultrafast dynamics process of Cu 1 . 81 S nanodisks (NDs) and Ag-Cu 1 . 81 S nanocomposites are investigated by using femtosecond Z-scan measurements and femtosecond time-resolved transient absorption spectrum , respectively. After decoration with Ag particles, Ag-Cu 1 . 81 S nanocomposites exhibit stronger saturable absorption and smaller saturable intensity at 600 and 800 nm. The carrier relaxation time is measured using femtosecond time-resolved techniques, and the results showed that the prolongation of the carrier relaxation time of the composite material can lead to a stronger saturation absorption effect.