共查询到20条相似文献,搜索用时 31 毫秒
1.
在准连续情况下, 通过求解低双折射光纤中含有拉曼效应的右旋与左旋圆偏振光所满足的耦合非线性薛定谔方程, 得到了归一化功率以及相位差的解析解. 利用解析解,推导出了椭圆率和方位角的表达式, 研究了拉曼效应和传输距离对偏振态演化的影响, 并用相平面法对椭圆率和方位角随着输入功率的变化进行了直观描述. 结果表明: 低双折射光纤在传输的过程中, 拉曼效应和传输距离都是影响其偏振态稳定性的因素, 均改变了椭圆率和方位角的演变周期以及振荡幅度. 相似文献
2.
D. V. Brazhnikov A. V. Taĭchenachev A. M. Tumaĭkin V. I. Yudin S. A. Zibrov Ya. O. Dudin V. V. Vasil’ev V. L. Velichansky 《JETP Letters》2006,83(2):64-68
The parameters of nonlinear absorption magneto-optical resonances in the Hanle configuration have been studied as functions of the ellipticity of a traveling light wave. It has been found that these parameters (amplitude, width, and amplitude-to-width ratio) depend strongly on the polarization of the light wave. In particular, the resonance amplitude can increase by more than an order of magnitude when the polarization changes from linear to optimal elliptic. It has been shown that this effect is associated with the Doppler frequency shift for atoms in a gas. The theoretical results have been corroborated in experiments in Rb vapor. 相似文献
3.
F. Koch D. Kovalev B. Averboukh G. Polisski M. Ben-Chorin 《Journal of luminescence》1996,70(1-6):320-332
We examine the polarization memory effect for porous Si excited by linearly polarized light. The various observations for the red-luminescing, slow band are discussed in the general framework of particle shape asymmetry. We show that because of the intrinsically nonlinear luminescence response, measurement parameters influence the polarization response. The preparation of porous Si with photoassisted etching is found to control the polarization retention parameter ρ. Using linearly polarized light during etching produces in-plane asymmetries. We find a substantial ρ-anisotropy linked to crystal symmetry planes and axes as a consequence of anisotropic etching. The effects are discussed with reference to current models of the light emission mechanism. 相似文献
4.
《中国光学快报(英文版)》2017,(5)
An elliptical initial polarization state is essential for generating mode-locked pulses using the nonlinear polarization rotation technique. In this work, the relationship between the ellipticity ranges capable of maintaining mode-locked operation against different pump power levels is investigated. An increasing pump power, in conjunction with minor adjustments to the polarization controller's quarter waveplate, results in a wider ellipticity range that can accommodate mode-locked operation. Other parameters such as noise, pulsewidth, and average output power are also observed to vary as the ellipticity changes. 相似文献
5.
Junji Yamauchi Takashi Ando Yasuhiro Akimoto Hisamatsu Nakano 《Fiber and Integrated Optics》1996,15(4):353-363
A wavelength filter consisting of single-mode and few-mode fibers is investigated numerically. A simple finite-difference beam-propagation method, in which a transparent boundary condition can be imposed, is developed for circularly symmetric waveguides. After confirming the validity of the numerical method by the mode-mismatch loss, we calculate the propagating field in the fiber wavelength filter, in which interference between LP01, and LP02 modes occurs. To improve the filtering operation, a depressed-index fiber is employed for the few-mode fiber. The effects of the radius and refractive index of the depressed section on the transmission power are revealed and discussed. Power is suppressed to less than 0.1% at 1.3 μm, while maintaining power transmission of more than 85% at 1.55 μm. It is also found that the filtering operation shifts to higher wavelengths as the input power is increased when we choose a self-focusing nonlinear material in the depressed section. 相似文献
6.
7.
Dmitry L. Markovich Andrei Andryieuski Maksim Zalkovskij Radu Malureanu Andrei V. Lavrinenko 《Applied physics. B, Lasers and optics》2013,112(2):143-152
In this paper, we analyze the theoretical limits of a metamaterial-based converter with orthogonal linear eigenpolarizations that allow linear-to-elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50 %, while the realistic reflection configuration can give the conversion efficiency up to 90 %. We show that a double layer transmission converter and a single layer with a ground plane can have 100 % polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design for virtually any frequency range of the electromagnetic waves. 相似文献
8.
The self-induced polarization change of femtosecond laser pulses passing through an isotropic optical glass is investigated.
It is shown that supercontinuum generations from femtosecond lasers tend to be identical for the incident beam with different
polarizations ranging from a large-ellipticity to a linear state when the incident laser power increases. Theoretical analysis
reveals that a transient intensity-dependent birefringence is induced in the glass sample by the laser pulse itself, and the
accumulated nonlinear phase shift leads to a change in polarization ellipticity. Simulation results are consistent with the
experimental observations.
PACS 42.50.Md; 42.65.Jx; 42.81.Gs; 77.22.Ej 相似文献
9.
R. S. Akopyan A. V. Galstyan G. G. Zakharyan Yu. S. Chilingaryan 《Technical Physics》2005,50(1):55-60
The polarization properties of thick anisotropic holographic gratings are studied theoretically and experimentally. The dependences
of the diffraction efficiency, ellipticity, and polarization orientation of the diffraction beam on the azimuth angle of polarization
of an incident Bragg beam are derived. The experimental data are shown to agree well with the analytical calculations. It
is found that the diffraction characteristics can be controlled in a wide range of incident polarization. 相似文献
10.
Ming-jian Shi Zhen Lei Ya-yan Xi Xue-qin Cao Hui-biao Liu Yuan-yuan Huang Xin-long Xu 《Annalen der Physik》2023,535(12):2300314
Polarized terahertz (THz) wave generation is of great significance for chiral and anisotropic sensing applications. However, how to manipulate amplitude, polarization, and ellipticity of the THz generation is still a fundamental challenge. Herein, polarized THz wave generation is achieved from a bilayer metamaterial consisting of T-shaped structure (TSS) and split resonator rings (SRRs) by combining Maxwell and hydrodynamic equations. The elliptically polarized THz wave can be synthetized directly from horizontally and vertically polarized THz components due to the orthogonal nonlinear photocurrents along the arm-directions of TSS and SRRs, respectively. Besides, the ellipticity and the orientation angle of the THz polarization ellipse can be modulated by the twist angle between the SRRs and TSS layers. The maximum ellipticity can reach 0.34 while the orientation angle is tunable from −0.45 to 0.48π by tuning the twist angle. This work proposes an interlayer coupling method for the polarized THz sources based on metamaterials in potential circular dichroism and chiral sensing applications. 相似文献
11.
12.
Gordon R Brolo AG McKinnon A Rajora A Leathem B Kavanagh KL 《Physical review letters》2004,92(3):037401
Strong polarization dependence is observed in the optical transmission through nanohole arrays in metals. It is shown that the degree of polarization is determined by the ellipticity and orientation of the holes; the polarization axis lies perpendicular to the broad edge of the ellipse. Furthermore, the depolarization ratio shows a squared dependence on the aspect ratio of the holes, which is discussed in terms of coupling into and out of the surface plasmon modes. The observed results will be useful for tailoring the polarization behavior of metallic nanophotonic elements in many applications, including surface plasmon enhanced optical sensing and ultrafast optical switching. 相似文献
13.
谢崇进 《中国光学快报(英文版)》2010,(9):844-851
Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-polarization modulation (XPolM) induced nonlinear polarization scattering can significantly degrade the transmission performance of PDM-QPSK coherent systems and change the perspective of dispersion management in optical coherent transmission systems. Some techniques to mitigate nonlinear polarization scattering in dispersion-managed PDM coherent transmission systems are discussed, including the use of time-interleaved return-to-zero (RZ) PDM formats, the use of periodic-group-delay PGD dispersion compensators, and the judicious addition of some polarization-mode-dispersion (PMD) in the transmission link. It is shown that if nonlinear polarization scattering can be well mitigated, a polarization multiplexed optical coherent transmission system with dispersion management could perform better than that without it. 相似文献
14.
P. Tekely V. G rardy P. Palmas D. Canet A. Retournard 《Solid state nuclear magnetic resonance》1995,4(6):361-367
A simple modification of the standard cross-polarization method designed for quenching the proton T1ρ dependence when studying polarization transfer is presented. It is demonstrated that by using this simple procedure, new and subtle details of cross-polarization dynamics, previously hidden by the T1ρ(1H) effect, can be observed in dipolar-coupled spin systems. 相似文献
15.
16.
Yu. A. Kravtsov J. Chrzanowski 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,63(1):129-133
Polarization of electromagnetic waves in magnetized plasma is studied in conditions, when
Cotton-Mouton effect is weak enough as compared with Faraday one. Evolution of
polarization state is described by new mathematical approach, namely, by angular variables
technique (AVT) which describes evolution of the angular parameters of polarization
ellipse in magnetized plasma. The method of consequent approximations is applied, which
uses the ratio (Ω
⊥/Ω
3) of
Cotton-Mouton and Faraday terms, as a small parameter of a problem and allows obtaining
simple analytical expressions for azimuthal and ellipticity angles in frame of the first
and second approximations. The phenomenon of ellipticity modulation and suppression by
Faraday rotation is revealed, which consists in ellipticity decreasing for stronger
Faraday rotation, what makes polarization closer to linear one. Numerical illustration of
the phenomenon are presented. It is shown that account of the second-order terms of the
method of consequent approximation provides an accuracy better than 1% even in conditions,
when small parameter
Ω
⊥/Ω
3
achieves the value 1/4. 相似文献
17.
In this paper, we formulate the radiative transfer problem as an initial value problem via a pair of nonlinear matrix differential equations (matrix Riccati equations or MREs) which describe the reflection (R) and transmission (T) matrices of the specific intensities in a plane-parallel geometry. One first computes R and T matrices of some small but finite layer thickness (equivalent optical thickness τ∼0.01 and then repetitively applies the doubling method to the reflection and transmission matrices R(τ)and T(τ) until reaching the desired layer thickness. The initial matrices R(τ0)and T(τ0) can be computed quite accurately by either of the following methods: multiple-order, multiple-scattering approximation, iterative method or fourth-order Runge-Kutta techniques. In addition, the reflection coefficient matrix of a semi-infinite medium satisfies an algebraic matrix equation which can be solved repetitively by a matrix method. MREs offer an alternative way of solving plane-parallel radiative transport problems. This method requires only elementary matrix operations (addition, multiplication and inversion). For vector and/or beam-wave radiative transfer problems, large matrices are required to describe the physics adequately, and the MRE method provides a significant reduction in computer memory and computation time. 相似文献
18.
The stimulation of a ring cavity filled with an isotropic medium with third order nonlinearity by plane monochromatic arbitrary polarized light is studied. An evolution of the stationary transmission with the change of the polarization of the incident light from circular to linear is discussed. For the linear polarized incident light additional branches of high transmission corresponding to elliptically polarized transmitted light and degenerating with respect to the rotation of the polarization vector are found. The stability of the stationary solutions is discussed. The possibility of the transmitted light polarization and intensity control by changing the polarization ellipticity degree of the incident light is shown. 相似文献
19.
The dependence of the polarization-and intensity-modulation group delay on the polarization of electromagnetic wave was studied experimentally for different transitions between the hfs components of the 87Rb D1 absorption line. It was found that the polarization-modulation delay strongly depends on the degeneracy structure of resonant transition and, in the general case, on the ellipticity of light-wave polarization. It is demonstrated that the polarization-modulation delay does not occur for the transitions not involving dark states. The polarization delay was studied as a function of the polarization ellipticity angle. The intensity-modulation delay was measured for the resonance radiation to show that it is observed for all 87Rb D1-line transitions and is independent of polarization. 相似文献
20.
Recent data on differential and total cross sections in the region 82 < Tπ (MeV) < 292 from SIN and CERN and an isolated polarization measurement formed the material for a πd phase-shift analysis. For virtually all cases χ2 < 1 could be reached, but extracted phase parameters are not unique. We emphasize the strong constraints polarization data would exert on presently ambiguous phase parameters. We present our results in Argand plots and briefly discuss their behaviour. 相似文献