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1.
Analytical nonparaxial vectorial electric field expressions for both Gaussian beams and plane waves diffracted through a circular aperture are derived by using the vector plane angular spectrum method for the first time,which is suitable for the subwavelength aperture and the near-field region.The transverse properties of intensity distributions and their evolutions with the propagating distance,and the power transmission functions for diffracted fields containing the whole field,the evanescent field and the propagating field are investigated in detail,which is helpful for understanding the relationship between evanescent and propagating components in the near-field region and can be applied to apertured near-field scanning optical microscopy. 相似文献
2.
The near-field diffraction of a nanometer aperture is studied in this paper according to the angular spectrum theory. The mathematic expressions of the near-field diffraction are presented, and the influences of the polarization of the electromagnetic field and the evanescent wave on the diffraction in near field are analyzed by means of vector and scalar diffraction theory, respectively. The transverse and longitudinal diffraction intensity distributions of a small aperture are numerically calculated, and the results show the near-field diffraction of a small aperture is influenced strongly by the vector property of the electromagnetic field and the evanescent component. 相似文献
3.
研究了沿光轴入射的傍轴光束在单轴左手介质中传输的矢量性质.通过平面角谱的方法得到了横电(TE)波和横磁(TM)波在单轴左手介质中传输的严格解,并得到了傍轴近似下的矢量传输模型.利用这一模型,分析得到垂直于光轴方向不同偏振态的入射光束在单轴左手介质中同时激发横向场和低阶纵向场.如果单轴左手介质的介电常数张量在沿垂直于光轴方向上的元素不相等,同时磁导率张量在沿垂直于光轴方向上的两元素也不相等(即z方向为光轴方向,x≠y,μx≠μy),那么入射光束激发的横向场的分布与入射光束的初始场分布和偏振态有关,而纵向场的分布与入射光束的偏振态无关,只决定于入射光束的初始场分布.
关键词:
傍轴传输
单轴左手介质
矢量效应 相似文献
4.
5.
Analytical vectorial structure of radially polarized light beams 总被引:2,自引:0,他引:2
Starting from the vector angular spectrum of the electromagnetic beam, the analytical vectorial structure of the radially polarized beams (RPBs) is presented. The energy flux distributions of the RPBs are demonstrated. The physical pictures of the RPBs are well illustrated from the vectorial structure. This particular electromagnetic field is entirely transverse magnetic, and on axis it only has a longitudinal (z) electric-field component (i.e., no transverse electric field and no magnetic field at all on axis). 相似文献
6.
7.
R. Martínez-Herrero P. M. Mejías I. Juvells A. Carnicer 《Applied physics. B, Lasers and optics》2012,106(1):151-159
A comparison is established between the contributions of transverse and longitudinal components of both the propagating and
the evanescent waves associated to freely propagating radially polarized nonparaxial beams. Attention is focused on those
fields that remain radially polarized upon propagation. In terms of the plane-wave angular spectrum of these fields, analytical
expressions are given for determining both the spatial shape of the above components and their relative weight integrated
over the whole transverse plane. The results are applied to two kinds of doughnut-like beams with radial polarization, and
we compare the behavior of such fields at two transverse planes. 相似文献
8.
M. W. Evans 《Foundations of Physics》1994,24(11):1519-1542
The relation is developed between rotation generators of the Lorentz group and the magnetic fields of free-space electromagnetism. Using these classical relations, it is shown that in the quantum field theory there exists a longitudinal photomagneton, a quantized magnetic flux density operator which is directly proportional to the photon spin angular momentum. Commutation relations are given in the quantum field between the longitudinal photomagneton and the usual transverse magnetic components of quantized electromagnetism. The longitudinal component is phase free, but the transverse components are phase dependent. All three components can magnetize material in general, but only the transverse components contribute to Planck's law. The photon therefore has three, not two, relativistically invariant degrees of polarization, an axial, longitudinal, polarization, and the usual right and left circular transverse polarizations. Since the longitudinal polarization is axial, it is a phase- free magnetic field. 相似文献
9.
O.N. Gadomsky S.V. Sukhov Yu.Yu. Voronov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):185-190
The self-consistent problem is solved for the interaction of two dipole atoms situated at arbitrary distance from one another
with the field of quasiresonant light wave. Atoms are considered to be linear Lorenz oscillators. Polarizing fields inside
the system include both Coulomb and retarding parts. The solutions obtained are investigated for the case when atoms have
the same polarizabilities and interatomic distance is much less than external light wavelength. Formulas for electric fields
inside and outside of small object are obtained. It is shown that longitudinal and transverse optical oscillations are possible
to exist inside small two-atom object. Dispersion laws of these oscillations depend upon interatomic distance and upon angle
between axis of the system and the direction of propagation of external wave. The field outside the small object in wave zone
is linearly polarized with the choice of linear polarization of external field. However, the directions of polarization of
these waves are different and depend essentially upon frequency. The amplitude of field outside small object in wave zone
is shown to depend essentially on the frequency of external field and interatomic distance. The results obtained are treated
as near-field effect in the optics of small objects making it possible to investigate the structure of small objects with
optical radiation.
Received 26 October 1998 and Received in final form 26 January 2000 相似文献
10.
Heterodyne optical feedback on a solid-state laser is experimentally investigated as an efficient tool to characterize coherently near-field evanescent waves. A well-known topography of evanescent field is obtained via a total internal reflection of the light beam emitted by a class B Yb:Er glass laser. A subwavelength size optical fiber tip is scanned to locally probe the resulting evanescent wave in the near field. After a frequency shifting using a pair of acousto-optic modulators, the collected light is optically reinjected to excite the relaxation oscillations of the laser. The resulting dynamical response simultaneously allows very sensitive measurements of the amplitude and the phase of the evanescent wave. Extension of these preliminary results to near-field optical microscopy is suggested and discussed. 相似文献
11.
We introduce the concept of degree of polarization for electromagnetic near fields. The approach is based on the generalized Stokes parameters that appear as expansion coefficients of the 3 x 3 coherence matrix in terms of the Gell-Mann matrices. The formalism is applied to optical near fields of thermally fluctuating half-space sources with particular interest in fields that are strongly polarized owing to resonant surface plasmons or phonons. This novel method is particularly useful when assessing the full vectorial characteristics of random evanescent fields, e.g., for near-field spectroscopy and polarization microscopy. 相似文献
12.
13.
The longitudinal optical field is a peculiar physical phenomenon that is always involved with the domain of near-field optics. Due to its extraordinary properties, it has recently attracted increasing attention in research and application. In this work, the longitudinal fields generated by the evanescent illumination of tightly focused, different polarized hollow beams are investigated. The focused light fields are numerically simulated according to vector diffraction theory, and their vector analysis is also carried out. The longitudinal fields on the focal plane are demonstrated experimentally using tip-enhanced scanning near-field microscopy. The simulation and experimental results show that the tightly focused radially polarized beam is suited to generating a stronger and purer longitudinal optical field at the focus. 相似文献
14.
A numerical simulation code for three dimensional problems of near-field optics has been developed using the volume integral equation with the moment method. The object is assumed to be continuous and macroscopic dielectric and can be treated by macroscopic Maxwell#x0027;s equations. The code can treat the large-scale moment method matrix that is obtained by the discretization of the volume integral equation. The resultant matrix equation is solved by an iteration method called the generalized minimum residual method with reasonable computational cost for simple problems of near field optics. Simulation of a simplified model of a scanning near-field optical microscope has been performed and basic polarization characteristics of the system have been investigated in detail. The code is also applied to the collection-mode of a photon scanning tunneling microscope, where the incident wave is the evanescent wave, and basic relation between near-field and far field i.e., output image, is recognized. 相似文献
15.
We present two-photon fluorescence near-field microscopy based on an evanescent field focus produced by a ring beam under total internal reflection. The evanescent field produced by this method is focused by a high-numerical-aperture objective, producing a tightly confined volume that can effectively induce two-photon excitation. The imaging system is characterized by the two-photon-excited images of the nanocrystals, which show that the focused evanescent field is split into two lobes because of the enhancement of the longitudinal polarization component at the focus. This feature is confirmed by the theoretical prediction. Unlike other two-photon near-field probes, this method does not have the heating effect and requires no control mechanism of the distance between a sample and the probe. 相似文献
16.
A self-consistent problem of interaction of two dipole atoms separated by an unrestricted distance with the field of a quasi-resonance
light wave was solved on the assumption that the investigated atoms are Lorentz linear oscillators and the polarizing fields
inside the system consist of the Coulomb and the retarded parts. The solution obtained was investigated for the case where
the atoms have the same polarizability and the distance between them is much smaller than the length of the external light
wave. Formulas for the electric fields inside a small object and outside it have been obtained. It is shown that inside a
small two-atom object there can take place longitudinal and transverse optical vibrations accompanied by corresponding dispersion
effects depending on the interatomic distance and the angle between the axis of the system and the direction of propagation
of the external light wave. The field outside the small object in the wave zone is linearly polarized when the external wave
has linear polarization. However, the direction of polarization of the corresponding waves is largely determined by their
frequency. It is also shown that the amplitude of the field outside the small object in the wave zone depends greatly on the
frequency of the external field and the interatomic distance. The effects observed are considered as a near-field effect in
optics of small objects. This phenomena makes it possible to investigate the structure of small objects with the use of optical
radiation.
Ul'yanovsk Branch of the Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 48 Goncharov Str., Ul'yanovsk,
432700, Russia; e-mail: gadomsky@quant.univ.simbirsk.su. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6,
pp. 765–770, November–December, 1999. 相似文献
17.
18.
We apply the theory of vectorial wave coupling in cubic photorefractive crystals subjected to ac-field to describe the transformation
of a momentary phase changes of one of the input beams into the output intensity modulation (the so-called grating translation
technique). In contrast to the previous studies, we take into account the change of the space-charge field amplitude across
the crystal owing to the coupling effects. The theory developed is employed to optimize the conditions for the linear signal
detection under polarization filtering for the transverse and longitudinal optical configurations. We also analyze the possibility
of the linear detection without polarization filtering.
PACS 42.70.Nq; 42.62.Cf; 42.87.Bg 相似文献
19.
近场光学虚拟光探针的数值分析 总被引:5,自引:4,他引:1
虚拟光探针是基于近场光学隐失场干涉原理产生的一种非实体探针,可以应用于近场光学超高密度存储、纳米光刻、近场光学成像、光谱探测、纳米样品的近场光学操作等领域。本研究采用三维时间域有限差分(FDTD)方法对近场光学虚拟光探针的光场分布特性进行了数值模拟计算和比较,分析了孔的形状、大小及偏振态等因素对虚拟光探针光场分布的影响,研究结果表明虚拟光探针的通光效率较普通的纳米孔径光纤探针提高10^2-10^4倍;其光场分布的中间峰的半峰全宽(即虚拟光探针的尺寸)在一定距离范围内基本保持不变,从而可以解决近场光学系统中纳米间距控制的难题,避免光学头与介质的磁撞。优化虚拟光探针的设计参量能有效的抑制虚拟光探针中的旁瓣。文章还给出了应用虚拟探针实现高密度光存储的原理方案。 相似文献
20.
Rosario Martínez-Herrero Pedro M. Mejías Ignasi Juvells Artur Carnicer 《Applied physics. B, Lasers and optics》2013,112(1):123-131
The contribution of the propagating and the evanescent waves associated with freely propagating non-paraxial light fields whose transverse component is azimuthally polarized at some plane is investigated. Analytic expressions are derived for describing both the spatial shape and the relative weight of the propagating and the evanescent components integrated over the transverse plane. The analysis is carried out within the framework of the plane-wave angular spectrum approach. These results are used to illustrate the behavior of a kind of donut-like beams with transverse azimuthal polarization at some plane. 相似文献