As a member of the 2D group IV monochalcogenides (MX; M = Sn, Ge; X = S, Se), SnS has attracted great interest due to its outstanding optical, electrical, and optoelectronic properties. Especially, SnS nanosheets material have a large absorption coefficient and high photoelectric conversion efficiency, it can be potentially used in optical modulators, saturable absorbers, solar cells, supercapacitors, and other optical devices. However, the nonlinear optical properties of SnS nanosheets and their applications in ultrafast photonics are seldom studied. In this paper, the nonlinear optical properties of SnS nanosheets have been characterized through a dual‐balance detection system, whose modulation depth is 5.8%. More importantly, 105th harmonic soliton molecule based on SnS saturable absorbers has been realized for the first time to the authors’ knowledge. A compact mode‐locked fiber laser with a pulse duration of 1.02 ps and a repetition rate of 459 MHz is realized near 1.5 µm. It is demonstrated that SnS nanosheets have outstanding nonlinear properties and play an extremely important role in the field of ultrafast photonics. 相似文献
We investigate periodic orbits and zoom-whirl behaviors around a Kerr Sen black hole with a rational number q in terms of three integers(z,w,v),from which one can immediately read off the number of leaves(or zooms),the ordering of the leaves,and the number of whirls.The characteristic of zoom-whirl periodic orbits is the precession of multi-leaf orbits in the strong-field regime.This feature is analogous to the counterpart in the Kerr space-time.Finally,we analyze the impact of the charge parameter b on the zoom-whirl periodic orbits.Compared to the periodic orbits around the Kerr black hole,it is found that typically lower energies are required for the same orbits in the Kerr Sen black hole. 相似文献
This paper employs a first-principles total-energy method to
investigate the theoretical tensile strengths of bcc and fcc Fe
systemically. It indicates that the theoretical tensile strengths
are shown to be 12.4, 32.7, 27.5~GPa for bcc Fe, and 48.1, 34.6,
51.2~GPa for fcc Fe in the [001], [110] and [111] directions,
respectively. For bcc Fe, the [001] direction is shown to be the
weakest direction due to the occurrence of a phase transition from
ferromagnetic bcc Fe to high spin ferromagnetic fcc Fe. For
fcc Fe, the [110] direction is the weakest direction due to the
formation of an instable saddle-point `bct structure' in the tensile
process. Furthermore, it demonstrates that a magnetic instability
will occur under a tensile strain of 14%, characterized by the
transition of ferromagnetic bcc Fe to paramagnetic fcc Fe.
The results provide a good reference to understand the intrinsic
mechanical properties of Fe as a potential structural material in
the nuclear fusion Tokamak. 相似文献
This paper compares the properties of silicon oxide and nitride as host matrices for Er ions.Erbium-doped silicon nitride films were deposited by a plasma-enhanced chemical-vapour deposition system.After deposition,the films were implanted with Er3+ at different doses.Er-doped thermal grown silicon oxide films were prepared at the same time as references.Photoluminescence features of Er3+ were inspected systematically.It is found that silicon nitride films are suitable for high concentration doping and the thermal quenching effect is not severe.However,a very high annealing temperature up to 1200° C is needed to optically activate Er3+,which may be the main obstacle to impede the application of Er-doped silicon nitride. 相似文献
Compared with real-valued complex networks, complex-valued dynamic networks have a wider application space. In addition, considering the existence of time delay and uncertainty in the actual system, the synchronization problem of fractional-order complex-valued dynamic networks with uncertain parameter and coupled delay is studied in this paper. In particular, the uncertain parameter is correlated with time delay. By using fractional derivative inequalities and linear delay fractional order equations, the synchronization of uncertainty complex networks with coupling delay is realized. Sufficient conditions for global asymptotic synchronization are obtained. The obtained synchronization results are applicable to most complex network systems with or without delay. Finally, numerical simulations verify the effectiveness of the obtained results.
In this exploratory study, near-threshold scattering of D and \begin{document}$\bar{D}^*$\end{document} meson is investigated using lattice QCD with \begin{document}$N_f=2+1+1$\end{document} twisted mass fermion configurations. The calculation is performed in the coupled-channel Lüscher finite-size formalism. The study focuses on the channel with \begin{document}$I^G(J^{PC})=1^+(1^{+-})$\end{document} where the resonance-like structure \begin{document}$Z_c(3900)$\end{document} was discovered. We first identify the two most relevant channels and the lattice study is performed in the two-channel scattering model. Combined with the two-channel Ross-Shaw theory, scattering parameters are extracted from the energy levels by solving the generalized eigenvalue problem. Our results for the scattering length parameters suggest that for the particular lattice parameters that we studied, the best fit parameters do not correspond to the peak in the elastic scattering cross-section near the threshold. Furthermore, in the zero-range Ross-Shaw theory, the scenario of a narrow resonance close to the threshold is disfavored beyond the 3\begin{document}$\sigma$\end{document} level. 相似文献