Mode-locking operation of an Er-doped fiber laser with (PEA)₂(CsPbBr₃)_n-1PbBr₄ perovskite saturable absorbers

Organic-inorganic hybrid perovskite materials have recently attracted considerable interest owing to their excellent optoelectrical properties, good environmental stability and variety of applications. The quasi-2D perovskites are also expected to have excellent application possibilities in the field of nonlinear optics, due to their distinctive structures and strong nonlinear absorption characteristics. However, ultrashort pulses from a mode-locked laser cavity based on a (PEA)₂(CsPbBr₃)_n-1PbBr₄ saturable absorber (SA) have not yet been reported. In this paper, we demonstrate that (PEA)₂(CsPbBr₃)_n-1PbBr₄ of 2D, quasi-2D and 3D structures exhibit excellent saturable absorption effects. By sandwiching the 2D, quasi-2D and 3D (PEA)₂(CsPbBr₃)_n-1PbBr₄ SAs between two fiber connectors in the Er-doped fiber laser, 17.4 MHz laser pulses with 492 fs, 922 fs and 950 fs pulse widths are obtained, respectively; the corresponding central wavelengths are 1569.5 nm, 1562.0 nm and 1558.8 nm. The experimental results show that the (PEA)₂(CsPbBr₃)_n-1PbBr₄ SA creates strong nonlinear effects, which means that it is a promising SA for the field of ultrafast lasers.