共查询到20条相似文献,搜索用时 6 毫秒
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Optical bistability based on surface plasmon polaritons in the Kretschmann configuration involving a Kerr nonlinear medium is described by analytical solutions. The conditions of forming the optical bistability with different parameters are explored. The resonant angle of surface plasmon polaritons varying with the incident light intensity also generates the phenomenon of bistability. The system could form optical bistability with the special thickness of the metal film and incident angle. This kind of system has potential application in all-optical networks. 相似文献
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The nonlinear response to applied fields of a four-level Y-type atomic system is investigated. The effect of laser intensity and quantum interference induced by spontaneous emission on optical bistability, optical multi-stability and Kerr nonlinearity is then discussed. It is found that the threshold of the optical bistability can substantially be reduced by the quantum interference. So, an enhanced Kerr nonlinearity with reduced absorption can be achieved. 相似文献
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We theoretically analyse the optical and optomechanical nonlinearity present in a hybrid system consisting of a quantum dot(QD) coupled to an optomechanical cavity in the presence of a nonlinear Kerr medium, and show that this hybrid system can be used as an all optical switch. A high degree of control and tunability via the QD-cavity coupling strength, the Kerr and the optomechanical nonlinearity over the bistable behaviour shown by the mean intracavity optical field and the power transmission of the weak probe field can be achieved.The results obtained in this investigation has the potential to be used for designing efficient all-optical switch and high sensitive sensors for use in Telecom systems. 相似文献
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The influence of the size parameter of the scatterers on ultrafast optical Kerr gate (OKG) imaging is investigated in highly scattering poly-disperse turbid media. The results show that in a poly-disperse turbid medium, which in our case, is a suspension of two different sized mono-disperse microspheres, the temporal and spatial behaviors of the light pulses transmitted through it are dominated by the smaller microspheres. The contrasts of the OKG images for the poly-disperse microsphere sample are closer to the contrasts of the OKG images for the smaller sized mono-disperse microsphere sample. 相似文献
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AbstractWe theoretically design a device composed of four nanoslits to dynamically modulate the propagation direction of light beam by embedding non-linear material and air, respectively. Directions of radiation fields are determined by the phase difference of the surface waves at the exit interface and distance of each slit. Numerical simulations using finite element method verify that the unidirectional excitation and beam focusing can be achieved easily by changing the intensity of incident light. 相似文献
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Fang Chen 《Journal of Modern Optics》2017,64(15):1531-1537
A plasmonic device for high-efficiency optical switch is proposed based on graphene coupled photonic crystals structure. The finite-difference time-domain simulation results show that the transmission and reflection ratio can be controlled by tuning the parameters of the graphene strip, such as chemical potential or width. And the corresponding contrast ratio can be 25 and 26.8 for a single and double graphene strips coupled photonic crystals structure, respectively. The results in this paper will have potential application in nanosensors and integrated photonic circuits. 相似文献
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We demonstrate the realization of on chip plasmon-induced transparency using dual ring resonators coupling to metal–dielectric–metal bus waveguide. The theoretical results agree well with the finite-difference time-domain simulative ones. Moreover, by adjusting the radius, width, as well as the coupling distance can efficiently operate the wavelengths and bandwidths of our filter. In theory, we propose a feasible method to improve the trade-off between transmission and quality factor. Finally, the ultra-compact structure possesses slow light effect and manifests a low group velocity, which provides a guideline to control the light and has potential application in optical filter and optical buffer. 相似文献
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Farshid Jahanbakhsh 《Journal of Modern Optics》2019,66(3):322-327
In this paper, based on the nonlinear coherent states formalism and using the Hamiltonian for a single mode field in a Kerr medium, the deformed photon-added nonlinear coherent states with negative m corresponding to the nonharmonic oscillators are constructed. In addition, some of the nonclassical properties associated with these states such as the Mandel parameter, quadrature squeezing and second-order correlation function are investigated. It is found that the deformed photon-added nonlinear coherent states with negative m for the one-mode field in a Kerr medium are nonclassical states. 相似文献
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Suxia Xie Mengxiong Wu Zhijian Li Hongjian Li Renlong Zhou Qiong Liu 《Journal of Modern Optics》2013,60(8):671-675
Fano resonances of a metal nanorod array with a symmetry breaking wedge and gain medium filling have been explored using the finite-difference time-domain method. Results show that a periodic symmetry breaking nanorod array supports Fano resonance due to the interaction between a hybridized dipolar plasmon mode of the nanorod and a narrower quadrupolar mode of the slice. By a tiny increase of the imaginary part of the dielectric constant of the gain medium, the Ohmic loss can be counteracted, and Fano resonance dip gets deeper significantly. Additionally, the modulation depth can be improved by changing the real part of the gain medium dielectric constant. The results found are useful for further develop of the devices on the basis of the Fano resonance and its modulation. 相似文献
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In this paper, a new anisotropic constitutive relation based on a modified couple-stress theory is defined for composite laminated Reddy beam. The theory contains only one material length-scale parameter in each ply of the composite laminated beam. The example of a cross-ply simply supported beam subjected to transverse load q0sin(πx/L) is presented. Numerical results show that the proposed beam model can capture the scale effect of the microstructure. The proposed model can be reduced to several models of the modified couple-stress theory by adopting the assumptions in Timoshenko beam, Bernoulli–Euler beam and material isotropy. It can be seen that the deflections and stresses obtained by the proposed beam model are smaller than those based on Timoshenko and Bernoulli–Euler beam assumptions. 相似文献
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Chang-Long Liao Guang-Lai Fu Sheng-Xuan Xia Hong-Ju Li Ling-Ling Wang 《Journal of Modern Optics》2018,65(3):268-274
We numerically and theoretically demonstrate a plasmon-induced transparency (PIT) at the mid-infrared region with finite-difference time-domain method. The system consists of an optically bright dipole mode and a dark quadrupole mode, which are supported by the graphene nanoring and graphene nanostrips, respectively. The coupling between the two modes introduces transparency window and large group delays. The pronounced PIT resonance can be easily modified by adjusting the geometric parameters and the Fermi level of graphene nanostructure. Our results suggest that the demonstrated PIT effect may be applicated in the slow-light device, active plasmonic switching, and optical sensing. 相似文献
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Arunangshu Sadhu 《Journal of Modern Optics》2017,64(2):156-163
A significant effect of nature of refractive index grading in the core of sub-wavelength diameter optical fibres on their performance characteristics in single-mode region is predicted and reported, for the first time, in connection with achievement of waveguide enhancement of Kerr nonlinearity-based optical processes. The analysis is based on a straightforward approach involving Marcuse spot size formulations for single-mode graded index fibre. Our formulations and results provide useful information and insight for optimum transverse dimensions of graded index fibre together with normalized core nonlinearity coefficient corresponding to profile exponent of the power law profile and should invite attention of system designers. 相似文献
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An electric field controlled two-dimensional higher order diffraction optical beam splitter has been realized based on a photorefractive higher order diffraction grating. In experiments, the splitter was produced by wave coupling (632.8 nm, 532.0 nm) at a small incident angle with a potassium lithium tantalate niobate single crystal. In the process of splitting, the incident beam of different wavelengths (632.8 nm, 532.0 nm) could be split into multi-output beams by the splitter. The influence of an externally applied electric field was studied and results show that the intensity of higher order diffraction could be controlled by the electric field. The polarization properties of higher order diffraction were discussed. An electric field controlled five–three optical beam splitter was investigated theoretically. 相似文献
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基于谱元法提出了一种弹簧元来模拟复合材料梁由于横向裂纹导致的轴弯耦合效应,分析复合材料裂纹梁中Lamb波的传播特性。由断裂力学的相关知识求得弹簧元的刚度,建立复合材料裂纹梁的损伤谱元模型。通过模拟复合材料裂纹梁内Lamb波传播,并和传统的有限元结果进行比较,验证了所提出模型的可行性和有效性。推导了频域内Lamb波各模态的能量计算公式,裂纹处的能量守恒证明了所提出模型的正确性,同时计算表明复合材料梁中裂纹处反射与透射的Lamb波各模态能量随着裂纹深度的变化规律具有单调性,结论可以为定量识别复合材料梁裂纹提供实用依据。 相似文献
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This article proposes a higher-order shear deformation beam theory for free vibration analysis of functionally graded carbon nanotube-reinforced composite sandwich beams in a thermal environment. The temperature-dependent material properties of functionally graded carbon nanotube-reinforced composite beams are supposed to vary continuously in the thickness direction and are estimated through the rule of mixture. The governing equations and boundary conditions are derived by using Hamilton's principle, and the Navier solution procedure is used to achieve the natural frequencies of the sandwich beam in a thermal environment. A parametric study is led to carry out the effects of carbon nanotube volume fractions, slenderness ratio, and core-to-face sheet thickness ratio on free vibration behavior of sandwich beams with functionally graded carbon nanotube-reinforced composite face sheets. Numerical results are also presented in order to compare the behavior of sandwich beams including uniformly distributed carbon nanotube-reinforced composite face sheets to those including functionally graded carbon nanotube-reinforced composite face sheets. 相似文献