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1.
?mer Kavaklolu Baruch Schneider 《International Journal of Infrared and Millimeter Waves》2008,29(4):329-352
A rigorous analytical representation for the multiple scattering coefficients of the fields radiated by an infinite grating
of dielectric circular cylinders excited by an obliquely incident plane electromagnetic wave is derived in terms of the “well-known
scattering coefficients of an isolated dielectric cylinder at oblique incidence” and “Schl?milch series”. In addition, a generalized
sum-integral grating equation is acquired for the multiple scattered amplitude of a cylinder at oblique incidence in the grating
in terms of the scattering coefficients of the insulating dielectric circular cylinder at oblique incidence.
相似文献
2.
Shogo Ura Kenji Kintaka Hideyuki Awazu Yasuhiro Awatsuji Junji Nishii 《Optical Review》2011,18(1):99-102
An interference exposure system using a phase-shifting mask was proposed for generating periodic sawtooth optical intensity
profile with chirp in period. Multiple space-harmonic waves are launched from the mask by diffraction, and the sawtooth optical
intensity is formed by interference based on Fourier synthesis after propagation through an air gap. The design concept merely
utilizing positive diffraction-order harmonics with tilt illumination of an exposure light and a design algorithm based on
time-reversed configuration for calculating required phase shift amount were proposed and discussed. A phase-shifting mask
for a blazed grating of very high chirp rate was designed to demonstrate its potential and feasibility. The grating period
changes from 2.2 to 3.1 μm gradually within 0.3 mm length. Sawtooth-like optical intensity profile was confirmed by theoretical
simulation as well as preliminary experimental results. 相似文献
3.
A lead-zirconate-titanate ceramic is used in an electrically controllable diffraction (ECD) grating for reflection of parallel
polarized light. The ECD grating used consists of a PZT ceramic with ten pairs of interdigital electrodes having 400 μm period
on its surface. The characteristics of the grating and its application to an optical modulator are demonstrated experimentllly
with a He−Ne 0.63 μm laser, obtaining a modulation of 60% with the applied peak voltage of 60 V at 24 kHz signal for the incident
angle of 60°. 相似文献
4.
Gustavo Forte Alberto Lencina Myrian Tebaldi Néstor Bolognini 《Optics Communications》2011,284(10-11):2494-2499
The self-image phenomenon by a volume grating is proposed and theoretically analyzed. A theoretical model based on a path integral formulation to describe wave propagation through the grating inhomogeneous medium is applied. A modified version of the scalar diffraction theory Fresnel propagator is obtained which allows calculating the diffracted field amplitude by the grating. The proposed model is applied to amplitude and/or phase volume gratings. Remarkable features appear, in particular at the fractional Talbot distance 0.125zT. In this case, if an in-phase real and imaginary grating modulation is considered a self-image intensity profile is observed for determined values of the absorptive and refractive parameters. On the other hand, a spatial comb intensity profile for a near half period shift between the real and imaginary grating modulations is found. 相似文献
5.
A chirped fiber grating with cladding made of uniaxial crystal material whose optical axis is parallel to the axis of grating,
i.e., z-axis is proposed. Electro-optic effect and elasto-optic effect in this kind of fiber gratings are theoretically analyzed
for the first time. The influences of the electric field and the strain applied to the fiber grating cladding along z-axis on Bragg wavelength λ
B and the reflectivity spectra of this kind of chirped grating are theoretically examined using coupled-mode theory and transfer
matrix method. The curves of Bragg wavelength λ
B as a function of an external electric field or the strain are theoretically obtained respectively for three kinds of uniaxial
crystal materials as the grating claddings. The calculated results indicate that when the axial electric field applied to
the grating cladding varies from 1 × 107 to 8 × 107 V/m, λ
B has the decreases of 0.12 nm, and when the applied strain varies from 0 to 0.04, λ
B has the decreases of 0.45 nm. 相似文献
6.
A quasi-collinear and partially degenerate four-wave mixing model is proposed to explain the optical phase-conjugation property
of various types of stimulated backscattering. According to this model, after passing through a phase-disturbed medium or
an aberration plate, the input pump beam can be resolved into two portions: a stronger undisturbed regular portion and a weaker
phase-disturbed irregular portion. These two portions interfere with each other and create a volume holographic grating in
the pumped region of the scattering medium. Only the stronger undisturbed portion of the pump field can excite an initial
backward stimulated scattering beam with a regular wavefront. When the latter (as a reading beam) passes through the induced
holographic grating, a diffracted wave will be created and then amplified together with the reading beam. A rigorous mathematical
analysis shows that under certain conditions the combination of these two portions (the reading wave and the diffracted wave)
of the backward stimulated scattering can be an approximate phase-conjugate field of the input pump field. The major theoretical
conclusions are basically supported by the experimental results based on a specially designed two-beam interference setup.
Zh. éksp. Teor. Fiz. 115, 431–448 (February 1999)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
7.
E. A. Dovolnov V. G. Mirgorod E. F. Pen S. N. Sharangovich V. V. Shelkovnikov 《Russian Physics Journal》2007,50(4):342-348
The temporal dynamics of spatial profiles of the first grating harmonic is modeled numerically with allowance for the absorption
in the transmission and reflection record geometry. The modeling is carried out for a theoretical model of record of spatially
inhomogeneous holographic diffraction gratings by an optical pulse train constructed from a solution of the kinetic photopolymerization
equations [1]. A dependence of the post-exposure gain on the recording conditions is analyzed numerically. The influence of
the pulse train characteristics on the diffraction grating efficiency is also investigated. The model parameters of the experimentally
investigated photopolymer material are estimated from a comparison of the experimental data on the kinetics of the diffraction
efficiency with the results calculated for the model presented in [1].
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 34–39, April, 2007. 相似文献
8.
本文提出了一种基于Metasurface产生任意柱矢量光束的方法.采用的Metasurface是在熔融石英上刻蚀空间变化的非周期光栅构成.非周期光栅会形成空变的有效双折射,从而对光场的偏振态空间分布进行调制.通过琼斯矩阵的方法分析得出这样的Metasurface可以将入射线偏振光转换为柱矢量光束,并且只需要改变入射线偏振光的偏振方向即可获得高阶庞加莱球赤道上任意一点的柱矢量光束.最后,用Metasurface搭建了一套简单、高效的柱矢量光束产生系统,实验结果与理论分析一致. 相似文献
9.
10.
M.A. Bader A. Selle O. Stenzel R. Delmdahl G. Spiecker C. Fischer 《Applied physics. B, Lasers and optics》2007,89(2-3):151-154
A high spectral resolution analysis of narrowband reflection filters based on resonant grating waveguide structures is presented.
A tunable high-performance dye laser with ∼ 0.15 cm-1 line width and a beam analyzing system consisting of three simultaneously controlled CCD cameras were used to investigate
grating waveguide resonances at wavelengths in the 694 nm and 633 nm ranges. A reflectivity of ∼ 91% and a line width of ∼ 0.55 nm
were measured and theoretically modeled for a resonant reflection filter specifically designed for the ruby laser wavelength
694.2 nm. For a second grating waveguide structure, designed for the helium-neon laser emission wavelength 632.8 nm, we observed
a thermal shift of its spectral resonance position of several nanometers, when increasing the sample temperature by some degrees.
An inverse thermal shift was observed when the structure was subsequently cooled down to room temperature. Our results suggest
implementation of grating waveguide devices combining a narrow line width with a tunability of the resonant response into
innovative concepts for reflection filter and sensor applications.
PACS 42.62.-b; 42.79.Dj; 42.79.Gn 相似文献
11.
A new approach for studying photorefractive gratings in two-wave mixing experiments by a phase modulation technique is presented. The introduction of a large-amplitude, high-frequency sinusoidal phase modulation in one of the input beams blurs the interference pattern and provides powerful harmonic signals for accurate measurements of the grating diffraction efficiency η and the output phase shift ϕ between the transmitted and diffracted waves. The blurring of the light fringes can be used to suppress the higher spatial harmonics of the grating, allowing a space-charge field with sinusoidal profile to be recorded. Although the presence of such a strong phase modulation affects the beam coupling in a rather complicated way, it is shown that for the special case of equal intensity input beams, the effect of the phase modulation on η and ϕ is reduced to a weakening of the coupling strength. The potentialities of the technique are illustrated in a study of refractive-index waves excited by running interference patterns in a Bi12TiO20 crystal. Expressions for the diffraction efficiency and the output phase shift are derived and used to match numerically calculated curves to the experimental data. The theoretical model is supported by the very good data fitting and allows the computation of important material parameters. PACS 42.40.Ht; 42.40.Kw; 42.70.Nq 相似文献
12.
Hiroshi Nomura 《Optical Review》2001,8(3):184-190
A focus monitor reticle having a novel grating structure is proposed. If a grating pattern has a property of being able to generate asymmetry between positive and negative diffraction orders, a defocus of the grating pattern can be translated to an easily measured pattern shift perpendicular to the optical axis. A possible grating for this purpose is composed of three components: opaque line, naked line and #x03C0;/2-phase-shifted groove. In particular, with their width ratio equivalent to 2/1/1, one of the two first-order beams disappears entirely. Consequently, tilted standing waves are formed by two-beam interference between zeroth-order and the other first-order on the image plane. This paper describes a new technique for measuring a defocus with a phase shift grating object. Good agreement between experimental sensitivities and theoretical expectation verifies that the technique achieves high accuracy of several nanometers or better. Applications of the technique show indicative ability in field curvature and astigmatism of the state-of-the-art scanner. 相似文献
13.
A dielectric grating leaky wave antenna with a substrate consisted of left handed material (LHM) is presented in this paper,
the case where the n = −1 space harmonic of TM mode radiating into the space is carefully investigated through the improved
perturbation analysis, which tremendously simplifies the analysis procedure with good calculation accuracy and brings considerable
physical insight into the overall behavior of the dielectric grating antenna. It has been found that the new leaky wave antenna
is of larger leakage constant than that of the traditional antenna with substrate of the right handed material (RHM). As a
result the dimension of the antenna could be largely reduced, which is of practical significance for some applications. Extensive
numerical results of the radiation characteristics are given to establish useful guidelines for the design of the new grating
antenna. 相似文献
14.
Martin?Gaal Ventsislav?Lavchiev Michael?Teuchtmann Holger?Schmidt Veronika?Rinnerbauer Christine?Hasenfu? Harald?Plank Gernot?Mauthner Kurt?Hingerl Emil?J.?W.?List 《Applied Physics A: Materials Science & Processing》2009,95(1):265-272
In this study, we present distributed feedback structure lasers which were fabricated by imprinting a grating directly into
a highly luminescent conjugated polymer. Based on the interplay between simulations and experimental results, we optimized
some basic parameters, crucial for the effective behavior of the structure. On the base of these parameters, new grating structures
were designed and fabricated by e-beam lithography and transferred to the polymer by the soft lithographic technique of “liquid
imprinting”. Due to these improved grating structures, the devices showed stable, low threshold lasing under photo-excitation
using a frequency doubled Nd:YAG laser. The obtained experimental results were again successfully modeled by simulating the
electromagnetic modes within the structure, and, in addition, the grating response to an electromagnetic field as a function
of the waveguide thickness and grating depth was monitored. 相似文献
15.
本文系统研究了基于泰伯效应(Talbot) 的位相可调掺镁铌酸锂二维六角位相阵列光栅及其光衍射成像, 对光栅占空比D、不同位相差Δφ、及泰伯分数β条件下的光栅近场光衍射强度分布进行了理论研究, 结果表明当光栅占空比D=52%、位相差Δφ=0.75 π、 泰伯分数β=0.2时, 光栅近场衍射光图像效果最佳. 实验设计与 制备了掺镁铌酸锂二维六角位相阵列光栅, 并对其进行了Talbot衍射光成像实验研究, 得到了不同位相差和不同泰伯分数β条件下光栅近场衍射 光图像, 实验结果与理论研究结果相符.
关键词:
二维六角位相阵列光栅
掺镁铌酸锂晶体
泰伯效应 相似文献
16.
We present a theoretical Fabry–Pèrot-Like model for the novel optical response of the subwavlength double-layers metal grating.
The Fabry–Pèrot-Like resonance phenomenon has been found in this structure, and the complex cavities model is carried out
for the interpretation of the resonant frequency shift due to the SPPs’ effect for the TM mode. The SPPs exist or not for
TE and TM mode lead to different resonance frequency. We conclude that the reflection coefficient minimum corresponds to the
condition satisfying the Fabry–Pèrot-Like resonance situation no matter for TE or TM mode.
PACS 42.79.Dj; 71.36.+c; 73.20.Mf; 78.66.Bz 相似文献
17.
Jiang Li Zhang Dong-sheng Zhang Wei-gang Kai Gui-yun Dong Xiao-yi 《Frontiers of Physics in China》2006,1(1):108-111
A method of fabricating dual-wavelength fiber Bragg grating with a uniform phase mask is demonstrated. Theoretical analysis
and numerical simulation using Matrix method are given. The moving exposing technique is adopted. Good control over the grating’s
reflectivity and the separation of the two Bragg wavelengths is enabled by adjusting the stretch, the length of the grating,
and the exposure. A grating with two equal transmission peaks of 19.5 dB is obtained by using this method, and the separation
of the two Bragg wavelengths is 0.78 nm.
Translated from Chinese Journal of Quantum Electronics, 2005, 22(1) (in Chinese) 相似文献
18.
In this contribution, an add/drop multiplexer that uses a mode-selective coupler and a holographically recorded slanted Bragg
grating in lithium niobate is demonstrated. A Bragg grating with a bandwidth of 0.1 nm allows for an add/drop efficiency of
about 96% with a cross-talk well above 22 dB applicable for wavelengths in the 1.5 μm window. Polarisation-independent operation
can be achieved by application of a bias electric field to compensate for the small mismatch of propagation constants of TE
and TM modes. The proposed scheme of an integrated-optical lithium niobate based device appears to be an interesting option
due to its potential for fast electro-optical switching.
PACS 42.40.Ht; 42.65.Hw; 42.70.Ln; 42.82.Cr; 42.82.Et 相似文献
19.
F. Brik N. Paraire T. Bouchemat M. Bouchemat 《Applied physics. B, Lasers and optics》2009,97(4):841-847
Many studies have been performed on III–V semiconductor all-optical switches with a Fabry–Perot or a waveguide structure.
Nonlinear effects have been observed in these devices but fast thermal effects occur which often limit their performances,
especially their speed.
We report a theoretical study of a waveguide device experimentally studied elsewhere, made of a III–V active material film
with a grating coupler and epitaxied on a Bragg reflector. 相似文献
20.
It was proved that the deposition of an overlay material onto a long-period fiber grating causes important shifts in the wavelengths of the typical attenuation bands that are caused by coupling between cladding and core modes [Opt. Lett. 27, 682 (2002)]. A theoretical model for analyzing a multilayer cylindrical waveguide is presented that permits the phenomenon to be understood and predicted. An overlay of higher refractive index than the cladding starts to guide a mode if a certain thickness value is exceeded. This causes large shifts in the resonance wavelength induced by the grating. One important application of this phenomenon to sensors is enhancement of the sensitivity of a long-period fiber grating to ambient conditions. Theoretical results are corroborated with experimental ones obtained by electrostatic self-assembly. 相似文献