Nonlinear optical properties of lead halide perovskite CsPbBr₃ for ultrafast pulse generation

Halide perovskites have attracted much attention in the field of nonlinear optics due to their strong quantum constraint, obvious exciton effect, and structural diversity. In this paper, lead halide perovskite CsPbBr 3 nanocrystals were synthesized with a size of 50–100 nm. The prepared CsPbBr 3 nanocrystals were deposited on the conical microfibers so that the nonlinear optical absorption features can be obtained. Based on a balanced twin-detector system, the modulation depth of the prepared CsPbBr 3 nanocrystals was determined as 9.2% and 7.2% at 1 µm and 1.5 µm, respectively. When the CsPbBr 3 saturable absorber (SA) was inserted into the Yb-doped fiber laser (YDFL), a stable noise-like pulse (NLP) mode-locking operation was obtained at a central wavelength of 1034 nm with a pulse duration of 415 fs. In the negative dispersive Er-doped fiber laser (EDFL), both the bound-state mode-locking operation with a pulse width of 971 fs and the conventional soliton mode-locking with a pulse width of 799 fs can be achieved at 1531 nm for the first time. These findings not only pave the way for a deeper understanding of the nonlinear optical properties in CsPbBr 3 nanocrystals but also provide a solid platform for further exploration of applications in ultrafast photonics.