共查询到20条相似文献,搜索用时 15 毫秒
1.
Jia Haur Wong Kan Wu Chunmei Ouyang Sheel Aditya Songnian Fu A. Chernov 《Optics Communications》2011,284(7):2007-2011
Polarization Rotation Locked Vector Solitons (PRLVSs) are experimentally observed for the first time in a fiber ring laser passively mode-locked by a single-wall carbon nanotube (SWCNT) saturable absorber. Period-doubling of these solitons at certain birefringence values has also been observed. We show that fine adjustment to the intracavity birefringence can swing the PRLVSs from period-doubled to period-one state without simultaneous reduction in the pump strength. The timing jitter for both states has also been measured experimentally and discussed analytically using the theoretical framework provided by the Haus model. 相似文献
2.
We consider the Maxwell equations for the electromagnetic-field propagation in a system of graphene planes with Anderson impurities.
A phenomenological equation is obtained in the form of an analog of the classical 1 + 1-dimensional sine-Gordon equation.
Electrons are considered within the quantum formalism taking into account the dispersion-law variations in the presence of
an impurity subsystem. The phenomenological equation is analyzed numerically. It was found that the formation of a forbidden
band in the graphene spectrum influenced the propagation of ultrashort optical pulses. 相似文献
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An analytical solution is presented for the electromagnetic scattering from an infinite-length metallic carbon nanotube and a carbon nanotube bundle. The scattering field and scattering cross section are predicted using a modal technique based on a Bessel and Hankel function for the electric line source and a quantum conductance function for the carbon nanotube. For the particular case of an isolated armchair (10, 10) carbon nanotube, the scattered field predicted from this technique is in excellent agreement with the measured result. Furthermore, the analysis indicates that the scattering pattern of an isolated carbon nanotube differs from that of the carbon nanotube bundle of identical index (m, n) metallic carbon nanotubes. 相似文献
5.
An analytical solution is presented for the electromagnetic scattering from an infinite-length metallic carbon nanotube and a carbon nanotube bundle.The scattering field and scattering cross section are predicted using a modal technique based on a Bessel and Hankel function for the electric line source and a quantum conductance function for the carbon nanotube.For the particular case of an isolated armchair (10,10) carbon nanotube,the scattered field predicted from this technique is in excellent agreement with the measured result.Furthermore,the analysis indicates that the scattering pattern of an isolated carbon nanotube differs from that of the carbon nanotube bundle of identical index (m,n) metallic carbon nanotubes. 相似文献
6.
The possibility of forming solitons in zigzag carbon nanotubes is investigated using the coupled equations for the classical function of the electron distribution and the Maxwell equations for an electromagnetic field. It is demonstrated that the solitons are generated as a result of correlated changes in the classical distribution function and the electric field induced by nonequilibrium electrons of a carbon nanotube. The effective equation describing the dynamics of the electromagnetic field is derived. The existence of solitons is confirmed by the results of numerical calculations. The characteristics of solitons are investigated as a function of the diameter of zigzag carbon nanotubes. 相似文献
7.
M. B. Belonenko N. G. Lebedev 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(1):151-155
The propagation of a variable electromagnetic field in arrays of “zigzag” carbon nanotubes at low temperatures is considered.
The electronic system of carbon nanotubes is analyzed using the Hamilton formalism with ignoring interactions with the phonon
subsystem because the electromagnetic field pulse is extremely short. An effective equation for the amplitude of the electromagnetic
field vector-potential was obtained. Solutions-analogues of solitons were revealed; these solutions corresponded to solitons
for the cosine electronic subsystem dispersion law. The dependences of the nonlinear solutions obtained on problem parameters
were analyzed. 相似文献
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By an improved projective equation approach and a linear variable separation approach, a new family of exact solutions of the (2+1)-dimensional Broek--Kaup system is derived. Based on the derived solitary wave solution and by selecting appropriate functions, some novel localized excitations such as instantaneous solitons and fractal solitons are investigated. 相似文献
10.
An asymptotic analysis of the Marchenko integral equation for the sine-Gordon equation is presented. The results are used for a construction of soliton asymptotics of decreasing and some non-decreasing solutions of the sine-Gordon equation. The soliton phases are shown to have an additional shift with respect to the reflectionless case caused by the non-zero reflection coefficient of the corresponding Dirac operator. Explicit formulas for the phases are also obtained. The results demonstrate an interesting phenomenon of splitting of non-decreasing solutions into an infinite series of asymptotic solitons. 相似文献
11.
Dumitru Mihalache 《Central European Journal of Physics》2008,6(3):582-587
A brief overview of recent theoretical results in the area of three-dimensional dissipative optical solitons is given. A systematic
analysis demonstrates the existence and stability of both fundamental (spinless) and spinning three-dimensional dissipative
solitons in both normal and anomalous group-velocity regimes. Direct numerical simulations of the evolution of stationary
solitons of the three-dimensional cubic-quintic Ginzburg-Landau equation show full agreement with the predictions based on
computation of the instability eigenvalues from the linearized equations for small perturbations. It is shown that the diffusivity
in the transverse plane is necessary for the stability of vortex solitons against azimuthal perturbations, while fundamental
(zero-vorticity) solitons may be stable in the absence of diffusivity. It has also been found that, at values of the nonlinear
gain above the upper border of the soliton existence domain, the three-dimensional dissipative solitons either develop intrinsic
pulsations or start to expand in the temporal (longitudinal) direction keeping their structure in the transverse spatial plane.
Presented at 9-th International Workshop on Nonlinear Optics Applications, NOA 2007, May 17–20, 2007, Świnoujście, Poland 相似文献
12.
依据磁场中Boltzmann输运方程及单层磁纳米管(SWNTs)的能量色散关系,对单个SWNTs中轴向磁场诱发的低温磁阻进行了数值计算.分析表明:当电子以低能输运时,SWNTs的磁阻有明显的Aharonov-Bohn(A-B)效应,与并SWNTs的能隙相对应. 相似文献
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Field-ion microscopy(FIM),a tool for surface analysis with atomic resolution,has been employed to observe the end structure of single-walled carbon nanotubes(SWCNTs).FIM images revealed the existence of open SWCNT ends,Amorphous carbon atoms were also observed to occur around SWCNTs and traditional field evaporation failed to remove them.Heat treatment was found to be efficacious in altering the end structures of SWCNT bundles.Carbon and oxygen atoms released from heated tungsten filament are believed to be responsible for the decoration imposed on the SWCNT ends. 相似文献
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The Co-filled carbon nanotubes (CNTs) film was produced on silicon substrate by electron cyclotron resonance microwave plasma chemical vapor deposition (ECR-CVD). The effects of different plasma powers of 200, 300, 400 and 500 W, on the morphology, structure and electrical properties of the CNTs film, were studied. The results showed that the surface density of the vertical nanotubes decreased when the plasma power was higher than 200 W. When plasma power of 300 W was used, the ends of the metal-filled carbon nanotubes (MF-CNTs) became straighter and more uniform. The Co-filled CNTs grown at 300 and 400 W had a current discharge at the applied voltages of 30 and 40 V, respectively. In addition, the surface morphology and the structure of the CNTs film were examined using scanning electron microscopy (SEM) and high-resolution field emission gun transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDXS) analyses were performed to identify the composition of the material inside the CNTs. 相似文献
17.
S.H. Jhang S.W. Lee D.S. Lee H.Y. Yu U. Dettlaff E.E.B. Campbell S. Roth Y.W. Park 《Current Applied Physics》2006,6(6):987
The switching of resistance between two discrete values, known as random telegraph noise (RTN), was observed in individual single-walled carbon nanotubes (SWNTs) and C60-filled SWNTs (the so-called peapods). The RTN has been studied as a function of bias-voltage and gate-voltage as well as temperature. By analyzing the features of the RTN, we identify three different types of RTN existing in the SWNT related systems. While the RTN can be generated by the various charge traps in the vicinity of the SWNTs, the RTN for metallic SWNTs is mainly due to reversible defect motions between two metastable states, activated by inelastic scattering with ballistic electrons. On the other hand, the noise for peapods can be attributed to the motion of C60 molecules in hollow space of SWNTs. 相似文献
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M. B. Belonenko N. G. Lebedev E. V. Sochneva 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(2):168-171
The theoretical possibility of the existence of dissipative solitons in an array of carbon nanotubes when they are subjected
to external uniform high-frequency electric field is discussed. An external alternating field is used for energy pumping of
the electron subsystem, while a finite relaxation time leads to energy dissipation. The generation of a periodic sequence
of electromagnetic pulses is revealed. 相似文献
20.
The possibility of analogs of dissipative solitons occurring in arrays of carbon nanotubes under the action of a high-frequency
external uniform electric field on the array has been established theoretically. The electromagnetic field has been considered
in terms of the Maxwell equations, and the conduction electrons in carbon nanotubes have been described by the Boltzmann kinetic
equation in the relaxation-time approximation. The external ac electric field serves for energy pumping of the electronic
subsystem, whereas a finite relaxation time leads to energy dissipation. The generation of a periodic sequence of electromagnetic
pulses has been revealed. This sequence can be used for producing terahertz frequencies. 相似文献