The team of Prof. Zhang Wei of Shenzhen University and the team of Professor Zeng Haibo of Nanjing University of Technology have made important progress in the research of ultrafast photonics of the few TiS2 nanosheets. The researchers have prepared a uniform morphology with small size distribution by colloid chemistry. Titanium disulfide nanosheets. After femtosecond laser Z scanning system testing, it was found that titanium disulfide nanosheets have wide-band nonlinear optical response from 400 nm to 1930 nm. Although two-dimensional materials with graphene and zero bandgap structure, experiments It is shown that when the number of layers is about 10 layers, titanium disulfide has a higher modulation depth (18%) than graphene (6.2%) at the communication band, and the experimentally measured saturation intensity is (9.91±0.32) MW. /cm2, also higher than the graphene 0.61 MW/cm2 intensity. In order to further verify its characteristics and promote the application of two-dimensional materials, the researchers designed two forms of titanium disulfide nanosheet nonlinear photonic devices, namely Pigtailed saturable absorber structure and micro-nanofiber composite structure. According to experimental requirements, the former is applied to an ultrashort-pulsed mode-locked fiber laser, achieving a central wavelength of 1569.5 nm, 1 The .04 ps pulse width is a stable output of the high quality mode-locked pulse sequence. The latter is creative. Using the same absorption mechanism, the noise suppression effect during the pulse transmission process is achieved, ie, the full light threshold. Experiments have proved to be based on fewer layers. The all-optical threshold device of titanium sulphide nanosheets can increase the pulse-to-noise ratio from 1.9 dB to 10.68 dB and maintain stable operation within 80 minutes. The results show that titanium disulfide has superior ultra-fast photonic characteristics.
This work has been published as a front cover paper on Advanced Optical Materials (DOI: 10.1002/adom.201701166).