The study of nonlinear optical responses in the mid-infrared(mid-IR)regime is essential for advancing ultrafast mid-IR laser applications.However,nonlinear optical effects under mid-IR excitation are rarely reported d...The study of nonlinear optical responses in the mid-infrared(mid-IR)regime is essential for advancing ultrafast mid-IR laser applications.However,nonlinear optical effects under mid-IR excitation are rarely reported due to the lack of suitable nonlinear optical materials.The natural van derWaals heterostructure franckeite,known for its narrow bandgap and stability in air,shows great potential for developing mid-IR nonlinear optical devices.We have experimentally demonstrated that layered franckeite exhibits a broadband wavelength-dependent nonlinear optical response in the mid-IR spectral region.Franckeite nanosheets were prepared using a liquid-phase exfoliation method,and their nonlinear optical response was characterized in the spectral range of 3000 nm to 5000 nm.The franckeite nanosheets exhibit broadband wavelengthdependent third-order nonlinearities,with nonlinear absorption and refraction coefficients estimated to be about 10^(-7)cm/W and 10^(-11)cm^(2)/W,respectively.Additionally,a passively Q-switched fluoride fiber laser operating around a wavelength of 2800 nm was achieved,delivering nanosecond pulses with a signal-to-noise ratio of 43.6 dB,based on the nonlinear response of franckeite.These findings indicate that layered franckeite possesses broadband nonlinear optical characteristics in the mid-IR region,potentially enabling new possibilities for mid-IR photonic devices.展开更多
Franckeite and cylindrite of franckite mineral group were examined in the transmission electron microscope. Selected-area electron diffraction indicated that in the structure exists a long period, belonging to an inco...Franckeite and cylindrite of franckite mineral group were examined in the transmission electron microscope. Selected-area electron diffraction indicated that in the structure exists a long period, belonging to an incommensurate modulation period. The incommensurate modulation in this kind of minerals results from sine undular structure sheets. The excellent correspondence between high resolution simulated computer image and observed image was obtained on the basis of the structure of franckeite and cylindrite which was put forward in this paper. First, the fact that in the structures of franckeite and cylindrite exist two kinds of structure sheets whose lattices are different has been proved by experiment, i. e. false tetragonal symmetrical galena structure sheets(t sheets)and false hexagonal SnS_2 sheets(h sheets). The two kinds of sheets are packed in order of htht…展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61975055)the Natural Science Foundation of Hunan Province,China(Grant No.2023JJ30165)+1 种基金the Natural Science Foundation of Shandong Province,China(Grant No.ZR2022QF005)the Doctoral Fund of University of Heze(Grant No.XY22BS14).
文摘The study of nonlinear optical responses in the mid-infrared(mid-IR)regime is essential for advancing ultrafast mid-IR laser applications.However,nonlinear optical effects under mid-IR excitation are rarely reported due to the lack of suitable nonlinear optical materials.The natural van derWaals heterostructure franckeite,known for its narrow bandgap and stability in air,shows great potential for developing mid-IR nonlinear optical devices.We have experimentally demonstrated that layered franckeite exhibits a broadband wavelength-dependent nonlinear optical response in the mid-IR spectral region.Franckeite nanosheets were prepared using a liquid-phase exfoliation method,and their nonlinear optical response was characterized in the spectral range of 3000 nm to 5000 nm.The franckeite nanosheets exhibit broadband wavelengthdependent third-order nonlinearities,with nonlinear absorption and refraction coefficients estimated to be about 10^(-7)cm/W and 10^(-11)cm^(2)/W,respectively.Additionally,a passively Q-switched fluoride fiber laser operating around a wavelength of 2800 nm was achieved,delivering nanosecond pulses with a signal-to-noise ratio of 43.6 dB,based on the nonlinear response of franckeite.These findings indicate that layered franckeite possesses broadband nonlinear optical characteristics in the mid-IR region,potentially enabling new possibilities for mid-IR photonic devices.
基金Project supported by the National Natural Science Foundation of China.
文摘Franckeite and cylindrite of franckite mineral group were examined in the transmission electron microscope. Selected-area electron diffraction indicated that in the structure exists a long period, belonging to an incommensurate modulation period. The incommensurate modulation in this kind of minerals results from sine undular structure sheets. The excellent correspondence between high resolution simulated computer image and observed image was obtained on the basis of the structure of franckeite and cylindrite which was put forward in this paper. First, the fact that in the structures of franckeite and cylindrite exist two kinds of structure sheets whose lattices are different has been proved by experiment, i. e. false tetragonal symmetrical galena structure sheets(t sheets)and false hexagonal SnS_2 sheets(h sheets). The two kinds of sheets are packed in order of htht…
