共查询到20条相似文献,搜索用时 31 毫秒
1.
含负折射率材料的一维光子晶体的光学传输特性 总被引:12,自引:2,他引:10
采用光学传输矩阵方法,模拟研究了由正折射率材料和负折射率材料交替组成的一维光子晶体的光学传输特性.计算了这种含负折射率材料的一维光子晶体的透射谱和色散关系.结果表明,在正入射时,含负折射率材料的光子晶体的带隙要比传统的光子晶体要大得多,并具有狭窄的透射带,从光学薄膜理论的色散关系出发解释了形成上述现象的原因.讨论了在不同的偏振模式下,光以中心波长入射时,反射率随着入射角度的变化关系.发现含负折射率材料的一维光子晶体具有更好的角度特性,可以用来实现对中心波长的全方位反射. 相似文献
2.
本文研究了硅柱在MnFe2O4磁性液体背景中排列成六边形结构的二维光子晶体的可调谐负折射特性. 利用平面波展开法和时域有限差分法理论研究了硅柱-磁性液体体系二维光子晶体的带隙结构、等频曲线和负折射现象随外磁场强度的变化关系. 模拟结果表明, 硅柱-磁性液体体系二维光子晶体工作在TE模式时, 其负折射特性可由外磁场调节. 在固定背景溶液的磁性颗粒体积分数和入射光频率时, 所研究的折射光束的偏转角和光子晶体的负折射率绝对值随外磁场的增大而增大, 而在固定背景溶液的磁性颗粒体积分数和外磁场强度时, 负折射角和负折射率的绝对值随入射光归一化频率增大而减小. 固定外场强度和入射光频率时, 所研究结构的负折射特性随背景溶液的磁性颗粒体积分数增大而变弱. 相似文献
3.
利用量子力学中的密度矩阵算符理论和迭代方法,导出莫尔斯(Morse)势阱中线性和三阶非线性光折射率改变的解析表达式,并以典型的GaAs/AlGaAs Morse势阱为例进行数值计算。数值结果表明,随着入射光强度增强,总的折射率改变将减少;随着势阱参数a的增大,总的折射率改变将减小;而随着载流子浓度的增加,总的折射率改变将增加。结果表明要获得较大的折射率改变,则需选取较小的入射光强度,较小的参数a,较大的载流子浓度,从而为实验研究提供理论依据。 相似文献
4.
Yoshisada Hayamizu 《Optical Review》2006,13(4):169-183
Internal or external conical refractions are strange optical phenomena appearing in biaxial crystal. In this paper the analysis
of internal conical refraction is derived using the ray tracing formulas for the biaxial crystals, after explaining the theory
of the ray tracing for the biaxial or uniaxial crystals. The double rings of conical refraction are also investigated; these
are affected by the polarization state or angular intensity distributions of the incident light beam causing conical refraction. 相似文献
5.
单轴晶体光轴任意取向时非寻常光的折射规律 总被引:2,自引:1,他引:1
在单轴晶体光轴任意取向的情形下 ,应用惠更斯原理导出了非寻常光折射方向的普遍计算公式 ,并给出了确定非寻常光线折射面和折射角的具体解。结合几种熟知的特殊情形进行了简要讨论 ,揭示了文中所得到的折射规律较之斯涅尔定律更具有普遍性 ,从而为光学系统中各类单轴晶体光学元件的应用提供了一个理论依据 相似文献
6.
《Optik》2014,125(24):7258-7261
This paper reports on the ambiguity present in the long-running Snell's law of refraction of light, which is based on the traditional ambiguous definitions of the angles of incidence and refraction in ray optics. To get rid of the said ambiguity, the refined unambiguous definitions of angles of incidence and refraction reported earlier by the author have been employed to give birth to the refined unambiguous statement of Snell's law of refraction. The most interesting physical insights that resulted from the refined unambiguous statement of Snell's law are: (i) in case of refraction of light of a particular colour while passing from one optical medium to another, the ratio of the sine of the angle of incidence and the sine of the angle of refraction is approximately equal to the refractive index of the second optical medium with respect to the first optical medium and (ii) the refractive index of an optical medium ‘b’ with respect to another optical medium ‘a’ is approximately equal to the reciprocal of the refractive index of the optical medium ‘a’ with respect to the optical medium ‘b’, and vice versa. These results are entirely novel and different from those existing in the traditional literature of ray optics. 相似文献
7.
б�����Ų��ڷǾ�����ײ���������е�����ͷ������� 总被引:1,自引:0,他引:1
提出碰撞吸收型等离子体的等效折射指数,重新计算了折射角,并与利用常规方法得到的折射角进行了比较。分析了等离子体密度和碰撞频率对折射角的影响。考察了斜入射电磁波在吸收型等离子体中的折射特性,并以一维非均匀碰撞吸收型等离子体为例,对斜入射电磁波的反射特性进行了考察。结果表明,等效折射指数的概念涵盖了入射角度的影响,在考察斜入射时更准确、便捷。 相似文献
8.
9.
Ping Yang K.N. Liou 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(4-5):300-306
The ray-tracing technique can be employed to simulate the scattering of light by a dielectric particle whose characteristic dimension is much larger than the incident wavelength. When a scattering particle is absorptive, a localized electromagnetic wave refracted into the scatterer is inhomogeneous, which requires the use of an effective refractive index to determine the propagation direction of the refracted ray. The effective refractive index for the first-order reflection–refraction event (i.e., the case for the ray-transmission from air into a particle) has been previously derived by the authors. In this study, we further develop recurrence formulae for the effective refractive indices associated with higher-order reflection–refraction events when the ray-transmission is from a particle to air. It is shown from the new formulae that effective refractive indices in this case depend upon ray history. Numerical results indicate that the real and imaginary parts of the effective refractive index are larger and smaller, respectively, than the real and imaginary parts of the inherent complex refractive index of an absorbing particle. Furthermore, if the particle faces associated with two sequential internal reflections are parallel to each other, the corresponding effective refractive indices are the same. 相似文献
10.
利用光波面和光波法线面的曲线方程,得出了光波面上光轴角和光线轴角的表达式。以此为基础,借助内锥折射和外锥折射的性质及对应光波面上的位置关系,推导了内锥折射锥顶角和外锥折射锥顶角的表达式。并以堇青石和黄玉为例给出了具体的锥顶角数值大小,分析了锥顶角很小的原因。 相似文献
11.
12.
Negative refraction in ferromagnetic materials under external magnetic field: a theoretical analysis
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We present a detailed theoretical analysis on the
possibilities and conditions for negative permeability and negative
refraction occuring in the magnetic materials with both pronounced
magnetic and dielectric responses to electromagnetic waves. The
results indicate that the permeability is always positive for
$\de=(2q+0.5)\pi$ ($\de$ is the initial phase difference of magnetic
components $h_{x}$ and $h_{y }$ of incident electromagnetic wave,
$q$ is integer), which means that it is difficult to realize
negative refraction. However, for $\de=2q\pi, \de=(2q+1)\pi$, or
$\de=(2q-0.5)\pi$, the negative permeability occurs at some range of
free procession frequency, which means that the refraction can
become negative under certain conditions. Further analysis reveals
that for general positive permittivity there are various
opportunities for realizing the negative refraction provided that
some requirements are met. One concludes also that the refractive
index for $\de=2q\pi$ case is similar to $\de=(2q+1)\pi$. The only
difference between two cases of $\de=2q\pi$ and $\de=(2q+1)\pi$ is
that the $x$-direction for $\de=2q\pi$ corresponds to the
$y$-direction for $\de=(2q+1)\pi$, and the $y$-direction for
$\de=2q\pi$ corresponds to the $x$-direction for $\de=(2q+1)\pi$.
The results are valuable for designing and analysing the complex
negative refraction of magnetic materials. 相似文献
13.
14.
利用可变光阑实现双轴晶体动态外锥折射 总被引:1,自引:0,他引:1
介绍了一种获得晶体动态外锥折射的方法.用全固态绿光激光器和双轴晶体kNbO_3,通过改变位于已消球差的双胶合透镜后表面处可变光阑的通光孔径,即改变入射光束的会聚角度,来实现入射光会聚角对外锥折射锥角的调制,由此得出双轴晶体kNbO_3外锥折射的锥角表达式.实验结果表明,周期性改变孔径光阑通光孔径的大小(入射光束的会聚角度)时,外锥折射锥角也同步地发生周期性的改变;外锥折射锥角等于入射于双轴晶体端面上的光线的会聚角.利用可变光阑可实现双轴晶体动态外锥折射并获得可控激光环,实验所测锥角角度与理论计算符合较好. 相似文献
15.
16.
从平面角谱理论出发,建立了光束在空气和玻璃界面折射的传输模型.基于这一模型,揭示了光学马格努斯效应中的横向角移现象.对于特定的线偏振和椭圆偏振光束,其折射场重心出现了横向角移,而当入射光束为圆偏振时,横向角移则会消失.在正负折射率界面,光束的横向角移产生了反转现象,这是由于光束在左手材料中发生了负衍射.超高折射率可明显地减少横向角移,而超低折射率则可显著地增强横向角移.这些发现将为如何调控和增强光学马格努斯效应提供理论依据.
关键词:
光学马格努斯效应
横向角移
圆偏振 相似文献
17.
一维光子晶体反常折射的数值分析 总被引:7,自引:4,他引:3
分析了一维光子晶体中产生反常折射的原因,根据波向量图对光在其中传播的方式做了定性的分析.根据一维光子晶体中具有波频率与波向量之间明确解析表达式的特点,指出利用此关系式能方便地对光在其中的传播方式进行深入的分析.利用这种方法,文中分析了光在其中传播的一些性质.指出光的偏移性质与角度和频率密切相关. 相似文献
18.
Xiang Xiong Shang-Chi Jiang Yuan-Sheng HuYu-Hui Hu Zheng-Han WangRu-Wen Peng Mu Wang 《Annals of Physics》2015
Controlling the polarization state, the transmission direction, the amplitude and the phase of light in a very limited space is essential for the development of on-chip photonics. Over the past decades, numerous sub-wavelength metallic microstructures have been proposed and fabricated to fulfill these demands. In this article, we review our efforts in achieving negative refractive index, controlling the polarization state, and tuning the amplitude of light with two-dimensional (2D) and three-dimensional (3D) microstructures. We designed an assembly of stacked metallic U-shaped resonators that allow achieving negative refraction for pure magnetic and electric responses respectively at the same frequency by selecting the polarization of incident light. Based on this, we tune the permittivity and permeability of the structure, and achieve negative refractive index. Further, by control the excitation and radiation of surface electric current on a number of 2D and 3D asymmetric metallic metastructures, we are able to control the polarization state of light. It is also demonstrated that with a stereostructured metal film, the whole metal surfaces can be used to construct either polarization-sensitive or polarization-insensitive prefect absorbers, with the advantage of efficient heat dissipation and electric conductivity. Our practice shows that metamaterials, including metasurface, indeed help to master light in nanoscale, and are promising in the development of new generation of photonics. 相似文献
19.
20.
DONG Hai-long WANG Jia-chun ZHAO Da-peng CHEN Zong-sheng LIU Rui-huang SHI Jia-ming 《光谱学与光谱分析》2018,38(11):3379-3384
太赫兹时域光谱技术可以快速准确地提取材料在太赫兹波段的光学常数。然而,其各组成部分在控制精度、响应误差、系统噪音以及实验操作、数据处理等方面的误差,将影响系统对材料光学常数提取的准确性。基于透射式太赫兹时域光谱系统的测量原理,分析了系统延迟线位置偏差对提取材料复折射率准确度的影响,建立了误差在样品测量过程中的传递模型,并利用MATLAB仿真了误差对提取样品复折射率影响。结果表明,样品折射率和消光系数的不确定度受到了系统延迟线位置偏差的影响,且系统延迟线位置偏差越大,样品的复折射率提取的不确定度也就越大。同时,相比消光系数,延迟线位置的偏差对样品折射率的不确定度具有更大的影响。该模型具有一定的实际意义和理论参考价值,可分析系统延迟线位置偏差对太赫兹时域光谱系统提取材料光学常数不确定度的影响,为优化太赫兹时域光谱系统提供理论指导。 相似文献