共查询到20条相似文献,搜索用时 0 毫秒
1.
用瑞利-傅里叶(Rayleigh-Fourier)数值方法及椭偏测量,研究了高反射正弦形浅光栅的偏振特性.当正向入射条件下,光栅周期与波长之比满足某一关系时,其反射光电场的两垂直方向分量相移差大的特性,制成了一种新颖的双折射滤光片,文中给出了这种双折射滤光片的初步实验结果. 相似文献
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General demonstration of principal states of polarization and real-time monitoring of polarization mode dispersion in optical fibres 下载免费PDF全文
We investigated the general properties of polarization effects in optical fibres and demonstrated the existence of socalled principal states of polarization (PSP), which mean the fixed points in mathematics, in different polarization effects,such as birefringence and polarization mode dispersion, by using fixed point theory. Furthermore, a time evolution vector is defined to describe the time evolution of polarization state in optical fibres, which is used to investigate the time evolution of polarization mode dispersion vector (PDV), including differential group delay and PSP. The experimental results of real-time monitoring of PDV by using this method are reported. To our knowledge, this is the first report on monitoring PSP evolution in optical fibres. 相似文献
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Yoshihiro Ohtsuka 《Optical Review》2001,8(6):498-499
Optical-frequency dependent polarization mode dispersion as well as modal birefringence of three kinds of specially designed
hollow-induced birefringent single-mode fiber are measured over an optical frequency range between 345 and 410 THz by optical
frequency-domain interferometry. 相似文献
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A numerical model based on ray optics formulation taking the optical path length into account was described and applied to
numerical investigations on a thermal birefringence compensation scheme proposed and experimentally demonstrated by Q, Lüet al. [Opt. Quantum Electron.28 (1996) 57]. Taking into consideration the thermal lensing effects of laser rods depolarization losses and spatial intensity
profiles of depolarized beams were calculated for the scheme. It was theoretically confirmed that using a polarization rotator
and imaging optics effective compensation for the birefringence in rods is possible for a wide range of pumping power. 相似文献
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Confined states and spin polarization on a topological insulator thin film modulated by an electric potential 下载免费PDF全文
We study the electronic structure and spin polarization of the surface states of a three-dimensional topological insulator thin film modulated by an electrical potential well. By routinely solving the low-energy surface Dirac equation for the system, we demonstrate that confined surface states exist, in which the electron density is almost localized inside the well and exponentially decayed outside in real space, and that their subband dispersions are quasilinear with respect to the propagating wavevector. Interestingly, the top and bottom surface confined states with the same density distribution have opposite spin polarizations due to the hybridization between the two surfaces. Along with the mathematical analysis, we provide an intuitive, topological understanding of the effect. 相似文献
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This work presents an explicit expression for the reflection and transmission coefficients of an anisotropic thin film in the general case in which the optical axis and the incident ray are arbitrarily directed in three dimensions. The polarization conversion quantities for reflected light from an anisotropic thin film are calculated and analyzed for two three-layered systems. With light incident from a dense medium, polarization conversion will be enhanced at a particular incident angle that exceeds the critical angle. 相似文献
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为了获取目标和背景的偏振信息,提高地面目标识别的准确度,提出一种光谱偏振成像探测系统。该系统采用旋转偏振片的方式对入射光的偏振状态进行调制,通过旋转滤光片进行光谱选择,从而实现光谱偏振成像探测。通过对该系统偏振度的探测精度进行实验测试,结果表明,所设计的光谱偏振成像探测系统达到4%的探测精度。利用该系统对地物背景中的迷彩伪装板进行了探测实验,分析所得的偏振度图像发现,目标在背景中较为明显,与草地及土壤背景区域偏振度的差值分别达到0.292和0.283。 相似文献
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研究了基于硅烯的静电势超晶格、铁磁超晶格、反铁磁超晶格中谷极化、自旋极化以及赝自旋极化的输运性质,分析了铁磁交换场、反铁磁交换场以及化学势对输运性质的影响,讨论了电场对谷极化、自旋极化以及赝自旋极化的调控作用.结果表明:当3种超晶格的晶格数达到10以上时,在硅烯超晶格中很容易实现100%的谷极化、自旋极化和赝自旋极化,而且通过调节超晶格上的外加电场可以使极化方向发生翻转,从而在硅烯超晶格中实现外电场对谷自由度、自旋自由度以及赝自旋自由度的操控. 相似文献
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Designing of a polarization beam splitter for the wavelength of 1310 nm on dual-core photonic crystal fiber with high birefringence and double-zero dispersion 下载免费PDF全文
We have proposed a novel kind of photonic crystal fiber which contains two asymmetric cores. The bireti'ingence and the dispersion are numerically analyzed based on finite element method when the size of the air holes and the pitch of two adjacent air holes are changed. It is shown that the proposed photonic crystal fiber has high birefringence up to the order of 10-2 and double-zero dispersion points are at the wavelengths of 1310 nm and 800 rim, simultaneously. At the same time, the normalized power and the extinction ratios of the proposed photonic crystal fiber have been simulated. It is demonstrated that, at the wavelength of 1310 rim, the x-polarized mode and the y-polarized mode are separated when the propagation distance is 2.481 ram. 相似文献
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P. Lesiak T. R. Woliński K. Brzdąkiewicz K. Nowecka S. Ertman M. Karpierz A. W. Domański R. Dąbrowski 《Opto-Electronics Review》2007,15(1):27-31
In this paper we present numerical and experimental results of propagation and polarization properties of the photonic liquid
crystal fibers (PLCFs) in which only selected micro holes were filled with nematic liquid crystal (LC) guest materials. As
a host photonic crystal fiber (PCF) structure, we used a commercially available highly birefringent PCF (Blazephotonics, UK).
A tunable laser operated at infrared has powered the PLCFs under investigation infiltrated by the 1550 nematic LC synthesized
at the Military University of Technology. Temperature induced changes of the polarization mode dispersion (PMD) as well switching
between fundamental and higher order modes and also single-core and two-core propagation were successfully demonstrated. 相似文献
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M. Schlsser T. M. James S. Fischer R. J. Lewis B. Bornschein H. H. Telle 《Journal of Raman spectroscopy : JRS》2013,44(3):453-462
In this article, we address the notoriously difficult problem to quantitatively link measured Raman depolarization values to theoretical polarizability tensor quantities, since quantum calculations do not incorporate experimental parameters. For this, we introduce a numerical model to calculate, for realistic experimental configurations, effective Raman line strength functions, Φ, which find their way into depolarization ratios, ρ. The model is based on interlinked integrations over the angles in the light collection path and a finite Raman source volume along the excitation laser beam. The model deals also with the conditional aperture parameters, associated with more than one optical component in the light collection path. Finally, we also can take into account polarization aberrations introduced by the sample cell windows. The procedure was fully tested for Raman depolarization spectra of selected hydrogen isotopologues. Distinct aspects affecting Raman depolarization data were validated, namely: (1) excitation polarization impurities; (2) extended Raman excitation volumes; (3) Raman light collection over finite solid angles; and (4) polarization aberrations introduced by optics in the light collection path. The correction of the experimental measurement data for the aforementioned effects resulted in depolarization ratios for the Q1(J " ) Raman lines of H2 and T2, which mostly differed by less than 5% from those obtained by quantum‐calculations. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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The number of least degrees of freedom required for a polarization controller to transform any state of polarization to any other output covering the entire Poincaré sphere 下载免费PDF全文
Using two typical types of polarization controller, this paper
analyses theoretically and experimentally the fact that it is
necessary to adjust at least three instead of two waveplates in
order to transform any state of polarization to any other output
covering the entire Poincar\'{e} sphere. The experimental results
are exactly in accordance with the theory discussed in this paper.
It has corrected the conventional and inaccurate point of view that
two waveplates of a polarization controller are adequate to complete
the transformation of state of polarization. 相似文献
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We investigate the neutron rich nuclei which can be described by shell model calculations in the p–sd and sd–pf model spaces. We quantify the effects of the core polarization on the multipole part (pairing and quadrupole) of the effective Hamiltonians. We show that proton core polarization contributions are responsible for the reduction of the neutron–neutron nuclear matrix elements which, in the recent shell model studies, appeared necessary between p–sd carbon and oxygen and sd–pf silicon and calcium nuclei. 相似文献
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We numerically investigate the complete chaotic synchronization mechanism of polarization mode of VCSEL with anisotropic optical feedback. Firstly, the synchronization quality of the x-linear polarization (LP) mode and the y-LP mode are both periodically changed with the angle θ between the polarizer and the light axes. Secondly, in a enough large scale region of the feedback coefficient and the injection current, where each LP mode can obtained good synchronization quality when the angle θ exists in the former half period region and the injection current is fixed at a certain value, which is over the threshold current. Under this condition, their synchronization quality is independent of the polarization states. By contrast, in the latter half period region of the angle θ where each LP mode can be obtained very instable and inferior synchronized quality. At last, the robustness of the synchronization scheme is sensitive to the internal and external parameter mismatch between the transmitter-VCSEL and the receiver-VCSEL. 相似文献