MOF-derived porous NiO-Co3O4 for high performance ultrafast pulse generation

Porous NiO-Co3O4 architectures, as one kind of novel metal organic frameworks (MOFs), have attracted extensive attention in the field of electrocatalysis and optoelectronics thanks to its large specific surface area, porous and adjustable pore size, structural and functional diversity. Although MOFs have made great achievements in many fields, the research on their ultrafast photonics fields is still in its infancy. Therefore, in this paper, NiO-Co3O4 polyhedra were synthesized by using zeolitic imidazolate framework (ZIF-67) as the metal source and sacrificial template. In addition, combining NiO-Co3O4 polyhedra with the microstructure fiber, nonlinear optical (NLO) absorption of the saturable absorber (SA) structure was characterized by two arm measurement technique. The experimental determination of the saturable intensity and modulation depth of NiO-Co3O4 polyhedra were 9.1 MW/cm(2) and 5.6%, which indicates that NiO-Co3O4 polyhedra possess excellent NLO absorption properties. Here, for the first time, it is proved that NiO-Co3O4 polyhedra can be served as an efficient SA to readily generate dual-wavelength mode-locking and high repetition rate output pulses up to 1.04 GHz (corresponding to 211th harmonic pulse) in erbium-doped fiber laser (EDFL), which is much higher than previous research results based on MOFs and their derivatives as SAs for ultrafast photonics. These experimental results demonstrate that the NiO-Co3O4 polyhedra SA derived from ZIF-67 is a new star which plays an important role in the field of ultrafast photonics.