Nonlinear optical properties investigation of 2D PbI2 material and its application in Yb-doped mode-locking fiber laser

Metal halides have attracted broad interest in advanced photonics and material synthesis fields due to their tunable bandgap, high charge mobility. As a member of metal halides, lead iodide (PbI2) has been widely applied in nuclear radiation detection and solar cells due to its photoelectric properties. However, the nonlinear optical (NLO) properties of PbI2, especially in the near-infrared band, are remain to be studied. In this paper, the NLO properties of two-dimensional (2D) PbI2 in 1 μm have been investigated by the Z-scan method, obtaining with a modulation depth of 7.3%, saturable intensity of 4.96 MW/cm2, nonlinear absorption coefficient of −3.77 × 102 cm/GW, and nonlinear refractive index of −1 × 102 cm2/GW, respectively. What 's more, by preparing 2D PbI2 material to be a saturable absorber (SA) and locating it in an ytterbium-doped fiber laser system, a stable mode-locking laser with a pulse width of 1.24 ns has been achieved. This work indicates that 2D PbI2 material can be deemed a promising SA material in the field of pulsed lasers.