2D titanium disulfide (TiS 2 ) is recently found to have strong light absorption properties from visible to infrared (IR) region. This feature is highly attractive for applications in nonlinear photonics; however, the mechanism of broadband light–matter interaction is yet to be determined and nonlinear photonic devices are not developed. Here, for the first time, the experimental evidence supporting the mechanism of the broadband nonlinear photoresponse in ultrathin TiS 2 nanosheets ranging from 400 nm to 1390 nm is reported through laser Z -scan measurements. High-performance nonlinear photonic devices operating in the telecommunication band are also demonstrated. A novel saturable absorber (SA) device is successfully fabricated based on a 2D TiS 2 -decorated fiber, which exhibits outstanding ultrashort pulse generation performance with pulse duration of ≈1.04 ps centered at 1569.5 nm. Furthermore, as a stable all-optical thresholding component, the device can effectively attenuate noise and boost the signal-to-noise ratio of the pulse from 1.90 to 10.68 dB. The findings indicate that TiS 2 -based SA devices can be developed into excellent highly nonlinear photonic devices, which may advance the development of TiS 2 -based optical communication technologies in the future.
Ning Jiang,Hongwei Chu,Zhongben Pan,Han Pan,Shengzhi Zhao,Dechun Li
Low-dimensional lead halide perovskites demonstrate remarkable nonlinear optical characteristics attributed to their distinctive physical structures and electronic properties. Nevertheless, the investigation into their nonlinear optical properties remains in its incipient stages. This study addresses this gap by precisely controlling solvent volumes to synthesize both 0D Cs 4 PbBr 6 and Cs 4 PbBr 6 /CsPbBr 3 perovskites. Remarkably, as saturable absorbers, both pure Cs 4 PbBr 6 and Cs 4 PbBr 6 /CsPbBr 3 composites exhibit favorable nonlinear optical properties within the C-band, showcasing modulation depths of 9.22% and 16.83%, respectively. Moreover, for the first time, Cs 4 PbBr 6 and Cs 4 PbBr 6 /CsPbBr 3 composites have been successfully integrated into erbium-doped fiber lasers to realize the mode-locking operations. The utilization of the Cs 4 PbBr 6 /CsPbBr 3 composites as a saturable absorber that enables the generation of conventional soliton mode-locked laser pulses with a pulse duration of 688 fs, and a repetition frequency of 10.947 MHz at a central wavelength of 1557 nm. Cs 4 PbBr 6 is instrumental in generating laser pulses at a frequency of 10.899 MHz, producing pulse widths of 642 fs at the central wavelength of 1531.2 nm and 1.02 ps at the central wavelength of 1565.3 nm, respectively. The findings of this investigation underscore the potential utility of 0D Cs 4 PbBr 6 and Cs 4 PbBr 6 /CsPbBr 3 composites as promising materials for optical modulation within fiber laser applications.
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