P-Polarized nonlinear surface polaritons in layered structures

We found an exact solution of Maxwell's equations, which describes the propagation ofp-polarized nonlinear surface polaritons and ofp-polarized nonlinear guided wave polaritons in two cases:i) in a film of a surface active material placed on a substrate described by a diagonal dielectric tensor whose elements depend on the amplitude of the electric field according to _{1 1}=_{2 2}= + (|E ₁|² + |E ₂|²), _{3 3}=, andii) in a film described by the same dielectric tensor (optically uniaxial nonlinear crystal) placed on a substrate with dielectric constant ₃ (optically linear medium). The power carried in the surface waves has also been exactly calculated.     

Surface polaritons and transmission in multi-layer structures containing anisotropic left-handed materials

We study the surface polaritons and optical transmission in multi-layer structures containing alternate anisotropic left-handed materials and isotropic right-handed materials. By means of the transfer matrix method, the dispersive relations of the surface polaritons are derived. In contrast to the single left-handed slab, the multi-layer structure is capable of supporting more surface polaritons due to the existence of more interfaces between the left-handed and right-handed layers. We further make detailed investigations of the optical transmission associated with the surface polaritons. Numerical results show that the variance of the thickness of each layer will obviously affect the positions of the transmission peaks, corresponding to the surface polariton branches. Moreover, the presence of the absorption in the anisotropic left-handed materials plays a crucial role in the optical transmission spectra. PACS 41.20.Jb; 73.20.Mf; 78.20.Bh; 42.70.Qs     

Wave polarization and left-handed materials in metallic magnetic composites

We theoretically investigate the existence of left-handed materials in metallic magnetic composites. We find that the composites behave as left-handed materials only when electromagnetic waves are right-hand circularly polarized under longitudinal magnetization or linearly polarized under transverse magnetization. The frequency range in which the metallic magnetic composites behave as left-handed materials depends on the wave polarization and characteristic parameters of the composites. Electric and magnetic dampings of the composites bring a reduction of the frequency band. Large damping may even destroy the existence of left-handed materials in metallic magnetic composites. PACS 73.50.Mx; 41.20.Jb; 42.25.Ja     

Dispersion of cylindrical surface plasmon polaritons in layered structures

The problem of the existence of cylindrical surface plasmon polaritons on thin metal conductors is considered. A dispersion relation is obtained and analyzed, the domain of existence of dispersion curve with a maximum is found, and parametric relations are derived.     

Vector breather of surface plasmon polaritons in left-handed material

A theory of an optical vector breather of self-induced transparency of surface plasmon polaritons is constructed. The nonlinear surface TM-modes propagating along the interface separating an isotropic medium and anisotropic left-handed material are investigated. A transition layer sandwiched between the connected media is described using a model of a two-dimensional gas of semiconductor quantum dots. Explicit analytical expressions for the shape and parameters of the surface vector breathers are obtained as well as simulations of the space-time dynamics of two-dimensional vector breathers presented with realistic parameters which can be reached in current experiments. It is shown that properties of a surface vector breather with phase modulation depends on the parameters of the quantum dots, the connected media and the transverse structure of the surface wave.     

梯度颗粒复合介质的光学双稳

重点研究了组分的梯度构形对带壳球形颗粒复合介质的光学双稳特性的影响.其中球形颗粒是由非线性核和介电函数具有梯度分布的线性壳组成.对于壳层介电函数具有幂指数分布的情况,通过求解麦克斯韦方程,得到各区域的势能分布函数,从而求得核内电场的数学表达式.数值研究发现,该复合介质的光学双稳阈值和区域与壳层的厚度及壳层的介电幂指数有关,随着壳层厚度增大或幂指数增大,双稳阈值将变宽.此外,还研究了正入射情况下复合材料体系的反射系数随外电场的变化情况, 发现其关系曲线是一条回线. 关键词： 梯度颗粒 复合介质 光学双稳     

Propagation of surface polaritons and total electromagnetic wave transmission through layered structures

Dispersion relations of coupled magnon-plasmon surface electromagnetic waves propagating along the interface between antiferrodielectric and uniaxial semiconductor are considered. Total transmission of infrared wave trough such layered structure induced by resonant excitation of the surface wave is investigated.     

Chiral surface plasmon polaritons on metallic nanowires

Chiral surface plasmon polaritons (SPPs) can be generated by linearly polarized light incident at the end of a nanowire, exciting a coherent superposition of three specific nanowire waveguide modes. Images of chiral SPPs on individual nanowires obtained from quantum dot fluorescence excited by the SPP evanescent field reveal the chirality predicted in our theoretical model. The handedness and spatial extent of the helical periods of the chiral SPPs depend on the input polarization angle and nanowire diameter as well as the dielectric environment. Chirality is preserved in the free-space output wave, making a metallic nanowire a broad bandwidth subwavelength source of circular polarized photons.     

非线性长程表面波的光学双稳态现象

本文利用衰减全反射技术,采用棱镜-折射率匹配液-银膜-半导体掺杂玻璃结构,首次用非线性长程表面波实现了光学双稳态现象。所得到的反射率对入射光功率的曲线具有明显的滞后回线的形式。     

Long-range surface polaritons in a supported thin metallic slab

It is shown that a thin metallic slab supported by a thick transparent slab may guide infrared surface polaritons (SP) with propagation lengths larger than those of SP in a semi-infinite metals. These long-range SP are “virtual” in the sense that their electromagnetic field is oscillatory across the supporting slab.     

Nonlinear surface magnetic polaritons in a nonuniform magnetic field

High-frequency surface magnetic polaritons of finite amplitude propagating along the interface between a ferrite and a nonlinear insulator in a weakly nonuniform, shaft-shaped external magnetic field are investigated theoretically. The analysis is based on employment of the variational method together with bilinear relations having the form of Lorentz’s lemma. It is shown that the wave dispersion and the transverse profile of a wave along the field nonuniformity depend significantly on the amplitude of the wave. Zh. Tekh. Fiz. 68, 92–95 (September 1998)     

Magnetic polaritons in metamagnet layered structures: Spectra and localization properties

The magnetic polariton propagation in metamagnet layered structures is theoretically studied by using a transfer matrix approach. The layered structures considered here are made up by the stacking of two different layers (also known as building blocks, named A and B), where one of them is a metamagnetic thin film (A), while the other is a non-magnetic insulator thin layer (B). We take into account both the antiferromagnetic (AFM) and ferromagnetic (FM) phases of the metamagnetic material. For the periodic arrangement, the bulk modes are characterized by two large symmetric bands, with non-reciprocal surface modes between them. The quasiperiodic metamagnetic structure is then built up by following the Fibonacci sequence, whose long-range order effect is then investigated, giving rise to an interesting self-similar spectra and a power-law profile.     

Optical bistability in fiber ring resonator containing an EDFA

In this paper, we study on optical bistability behaviors in a double-coupler ring resonator, in which an erbium-doped fiber amplifier (EDFA) is inserted into the ring for counteracting the loss by the gain of EDFA. The two groups of transmitted and reflected optical bistability loops under different parameters are investigated symmetrically. According to our optimum design of this new optical bistable device, the switching power can be less than 60 mW.     

Coupling of surface plasmon polaritons and light in metallic nanoslits

We clarify the nature of coupling between surface plasmon polaritons (SPP) and transmitted light in metallic nanoslit structures. The coupling strength is found to be the product of the geometric opening ratio, the aperture momentum, and the Fabry-Perot factor. We determine the effective coupling, which includes corrections due to other SPPs, and show that this effective coupling causes enhanced transmission with redshifted or blueshifted transmission peaks. Without coupling, SPP is proven to suppress transmission due to the equipartition of diffraction orders. These results show good agreement with experiment.     

Optical bistability of a layered semiconductor in the exciton absorption region

The effect of specific features of the exciton and phonon spectra of layered semiconductors on the conditions of realization of optical bistability in the exciton absorption region has been theoretically investigated by the Green’s function method. By the example of the 2H polytype of PbI₂, it is shown that effective exciton scattering from low-energy bending-wave vibrations leads to a blue shift of the frequency range of bistability realization and its narrowing; expansion of the temperature range of bistability observation; and a shift of the hysteresis loop to higher intensities, accompanied by a decrease in its height and width. The possibility of observing polarization optical bistability, which is related to the dependence of the exciton energy spectrum on the propagation direction of a light wave in a crystal, is also substantiated.     

Optical bistability in one-dimensional photonic band gap structures with coupled nonlinear defects

Using the transfer matrix method, we study the transmission property of one-dimensional photonic band gap structure with two coupled nonlinear defects separated by a linear middle layer and find that such composite structure exhibits a bistability that’s strongly dependent of the linear middle layer. The switching threshold values can be greatly reduced just by choosing the proper parameters of the linear middle layer.     

Photonic bandgap structures for long-range surface plasmon polaritons

Propagation of long-range surface plasmon polaritons (LR-SPPs) along periodically thickness-modulated metal stripes embedded in dielectric is studied both theoretically and experimentally for light wavelengths in the telecom range. We demonstrate that symmetric (with respect to the film surface) nm-size thickness variations result in the pronounced band gap effect, and obtain very good agreement between measured and simulated (transmission and reflection) spectra. This effect is exploited to realize a compact wavelength add-drop filter with the bandwidth of 20 nm centered at 1550 nm. The possibilities of achieving a full bandgap (in the surface plane) for LR-SPPs are also discussed.     

Optical bistability of subwavelength metallic film coated by Kerr dielectric gratings

We studied the optical bistability of subwavelength metallic film coated by Kerr dielectric gratings numerically. It is found that the effect of optical bistability in the structure is explained by the excitations of the coupled surface plasmon polaritons at the coated metallic films. The effect of thickness of the metallic films on bistability loop is analyzed in detail, and the authors attribute the change of the bistability loop to the lifetime of the coupled surface plasmon polaritons.     

含特异材料的光量子阱频率特性研究

基于传输线加载集总元件的方法制备光量子阱. 对阱内物质为光子晶体和左手材料两种情况下的传输特性进行比对. 结果表明局域模个数与阱内物质的周期数相同; 左手材料情况下光量子阱具有尺度小、 便于调节的优点.实验结果与理论结果相符合.