共查询到20条相似文献,搜索用时 15 毫秒
1.
I. A. Chernykh D. A. Mamichev Yu. V. Grishchenko V. V. Roddatis M. L. Zanaveskin M. R. Shcherbakov A. A. Fedyanin E. G. Novoselova I. S. Smirnov A. N. Marchenkov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(5):941-944
Nanostructures consisting of metal nanogratings made of Au on quartz substrates are produced. The structural characteristics
of samples are studied using atomic force and scanning electron microscopies (AFM and SEM). The optical properties of samples
in the visible spectral region are also studied. The studies show that these nanostructures are characterized by a high degree
of periodicity and the nanowire profile shape is close to the rectangular one. Effective excitation of surface plasmon-polariton
waves is observed in nanogratings; in this case the effectiveness of their excitation depends considerably on the polarization
of exciting radiation and on the grating filling factor. It is established that various types of plasmon-polariton waves (local
or traveling waves) can be excited depending on the grating filling factor. Optical effects observed in the given structures
can be used to produce high-speed sensor and optoelectronic elements based on them, such as highly sensitive new-generation
biosensors, optical filters, polarizers, and modulators. 相似文献
2.
Extraordinary Transmission through Metallic Grating with Subwavelength Slits for S-Polarization Illumination 下载免费PDF全文
Based on the rigorous coupled-wave analysis algorithm, we have systematically analysed the effect of the geometrical parameters of a dielectric film coated metallic grating with subwavelength slits on extraordinary optical transmission for s-polarization illumination. Results show that the dielectric film which sustains a waveguide electromagnetic mode on the top of the metallic lamellar grating can strongly enhance the transmittance, the positions of the transmission peaks are mainly determined by the period of the metallic grating, the thickness and refractive index of the dielectric film. This structure shows potential applications in excellent polarizers or polarization-isotropic devices at infrared spectral range by appropriately choosing the geometrical parameters. 相似文献
3.
Coupling of surface plasmon polaritons to radiation modes by use of a one-dimensional subwavelength dielectric grating on a thin metal slab is discussed. The surface plasmon waves obtained in Kretschmann configuration are resonant outcoupled to radiation modes by using a subwavelength dielectric grating. A peak outcoupling efficiency is predicted to be 74.57% with rigorous coupled-wave analysis. In addition, potential applications of these results in the design and improvement of various optoelectronic devices, such as polarizers, wavelength filters and biochemical sensors are discussed. 相似文献
4.
Improving the polarimetric measurement accuracy of the polarization CCD camera is a fundamental task in the remote sensing of the earth. This paper presents a simple approach for estimating the degree of polarization errors caused by the orientation angles uncertainty of the instrument polarizers. We show that the measured degree of polarization error for a certain orientation angle of the instrument polarizers in the same spectral band depends on the polarization state (polarization angle or degree of polarization) of the incident light. In order to evaluate the polarimetric measurement performance of the instrument, the average degree of polarization error is defined based on the assumption that the incident light beams have equal polarization angle probability. The simulated test showed that the average degree of polarization errors of the 3 polarized spectral bands in the airborne polarization CCD camera is nearly equal because of the same orientation angles uncertainty of the instrument polarizers, though the instrument polarizers in the 3 polarized spectral bands are equipped a little differently; the instrument often encounters a large average degree of polarization errors for the large degree of polarization of the incident beams. 相似文献
5.
We present results of the fabrication and measurements on reflective polarizers consisting of stacked bi-layer subwavelength metal gratings prepared on GaAs (100) substrates. These linear gratings were fabricated using electron-beam direct-writing lithography and the lift-off method with periods less than the wavelength of light used for measurements. At normal incidence, the polarizer reflects the light polarized perpendicular to the grating lines (transverse magnetic polarization, TM polarized) but absorbs parallel-polarized light (transverse electric polarization, TE polarized). By optimizing structural parameters, the polarization extinction ratio close to 20 has been experimentally achieved at wavelength of 650 nm. 相似文献
6.
Yamada I Yamashita N Tani K Einishi T Saito M Fukumi K Nishii J 《Optics letters》2011,36(19):3882-3884
A mid-IR wire-grid polarizer with a 500 nm pitch was fabricated on a low toxic chalcogenide glass (Sb-Ge-Sn-S system) by the thermal imprinting of periodic grating followed by the thermal evaporation of Al metal. After imprinting, deposition of Al on the grating at an oblique angle produced a wire-grid polarizer. The fabricated polarizer showed polarization with TM transmittance greater than 60% at 5-9 μm wavelengths and an extinction ratio greater than 20 dB at 3.5-11 μm wavelengths. This polarizer with a high extinction ratio can be fabricated more simply and less expensively than conventional IR polarizers. 相似文献
7.
Chun-Ting Lin 《Optics Communications》2011,284(1):195-200
An athermal metal-free planar waveguide concave grating demultiplexer is proposed. We designed the dielectric mirror at the grating facet instead of coating with the metal on the back wall of the grating facet. The transfer-matrix method is introduced to design the dielectric mirror and the reflectance spectral responses of the 2D waveguide structure are simulated using the FDTD software (RSoft, Inc.). To reduce the temperature sensitivity of the device, the three-focal-point method is introduced. We use the design example to show the high-reflectance bandwidth of the dielectric mirror. The fabrication errors are also taken into consideration. By using the numerical model of the scalar diffraction theory, the flat-top spectral responses of the channels are simulated. 相似文献
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9.
二元衍射光栅式偏光器件的设计 总被引:1,自引:0,他引:1
本文利用双折射晶体刻划成的二元衍射光栅的衍射偏振特性,设计了偏光器件(可分别对o光或e光起偏);偏光分束器件(包括非对称及对称偏振分束两类),并对有关参数对设计的影响进行了讨论. 相似文献
10.
We propose a unique optical system for measuring the retardation of birefringent films using a pair of liquid crystal (LC) gratings; that is, the examined birefringent films are inserted between two LC gratings. Because the LC grating functions as a polarization beam splitter for circularly polarized light, the proposed system is optically equivalent to the measurement system using a pair of two circular polarizers. First, the polarization splitting performance of the LC grating is discussed. It is found that a sufficiently high voltage (such that the retardation is less than a half wavelength) has to be applied for the almost pure circularly polarized diffracted light. Next, the measurement of the retardation of a homogeneous LC cell as an examined birefringent film was demonstrated using the proposed method. The proposed method is revealed to have the same measurement performance as that of the conventional method using a pair of linear polarizers and has an advantage that there is no need for the optic axis of the test birefringent specimen to be set at a specific angle. 相似文献
11.
José Luis Martínez Pascuala García-Martínez María del Mar Sánchez-López Ignacio Moreno 《Optics Communications》2011,284(10-11):2441-2447
In this work we present the application of a simple physical model to accurately predict the broadband spectral transmittance and colorimetric properties of a twisted-nematic liquid crystal display (TNLCD). We spectroscopically calibrate the retardance parameters to evaluate the spectrum of the light transmitted by a TNLCD sandwiched between two linear polarizers. When the TNLCD is illuminated with a broadband light source, the full spectrum can be predicted as a function of the addressed gray level for any arbitrary orientation of the polarizers. Thus, the color of the transmitted light can be also be estimated with very good accuracy. As an example, a polarizers' configuration is shown that yields, without using color filters, a relatively large color gamut compared to the standard configuration. Experimental results confirming the validity of such predictions are presented, both on the measured spectral responses as well as on the trajectories at different chromatic diagrams. 相似文献
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13.
Skaar J 《Optics letters》1999,24(15):1020-1022
A new, simple method for characterization of fiber Bragg gratings is proposed. The group delay of the grating is obtained from measurement of the spectral reflectivity response of a grating that is interfering with a bare-fiber end reflection. 相似文献
14.
偏振片在诸多光学系统中有着重要的应用。亚波长介质光栅可用作正入射偏振片,在高能激光系统中有着广泛的应用前景。为了探究波长为1 064 nm的纳秒脉冲激光对于亚波长全介质光栅的诱导损伤特性,使用了粒子群优化算法结合严格耦合波分析设计了光栅的几何参数,计算表明亚波长光栅偏振片在入射光波长1 064 nm附近带宽0.5 nm内,平均消光比为1 500。使用了紫外曝光配合离子束刻蚀的工艺制备了HfO2光栅,并对其纳秒脉冲激光损伤阈值进行了测试。测试结果表明S光损伤阈值约为P光损伤阈值的5倍,且都大于5 J/cm2。结果表明亚波长全介质光栅偏振片可广泛用于正入射激光系统中。 相似文献
15.
A novel method for rapid polarization measurement is suggested. The method is based on a periodic space-variant polarizer that can be realized by use of subwavelength metal-stripe gratings. The Stokes parameters of the incident beam are determined by Fourier analysis of the space-variant intensity transmitted through the grating, thus permitting real-time polarization measurement. We discuss the design and realization of such polarizers and demonstrate our technique with polarization measurements of CO(2)-laser radiation at a wavelength of 10.6mum. 相似文献
16.
The scattering and guidance of electromagnetic waves from a two-dimensionally (2D) periodic metal grating structure are investigated here. With the spectral domain analysis the dispersion characteristics for this structure are obtained. Properly taking into account the hybrid mode nature of the propagation problem the effects of mode coupling betweenTE andTM modes are examined. Numerical results will provide us valuable information for the design of new devices in 2D periodic structure, particularly in millimeter-wave frequency range, such as antennas, filters, couplers and distributed reflectors. 相似文献
17.
Spectral calibration is important for a Fourier domain optical coherence tomography (FD-OCT) system. A new spectral calibration method for FD-OCT is presented. Through the iterated mapping of spectral interferograms detected by an optical spectrum analyzer and the CCD grating spectrometer, multiple groups of calibration coefficients are obtained. By comparing the effects of these coefficients on improving the amplitude of the axial point spread function (PSF), optimum coefficients are obtained. In this method, no additional calibration laser source is needed, reducing the complexity of the system. The cross-sectional images of a glass plate in milk are acquired, and the experimental results indicate that the axial resolution and signal-to-noise ratio (SNR) are effectively improved with the proposed spectral calibration method. 相似文献
18.
光纤光栅法布里-珀罗传感器频分复用技术 总被引:2,自引:0,他引:2
理论分析了光纤光栅法布里-珀罗(F-P)传感器频分复用技术的原理,并给出了信号处理对腔长选取的要求。数值模拟结果表明,不同腔长的传感器具有不同的谐振条纹频率,为保证频域中的信号不发生重叠,要求不同光纤光栅法布里-珀罗传感器间的腔长之差必须大于光纤光栅的长度。进一步的实验及模拟分析结果发现,温度等待测量的变化仅仅使光纤光栅法布里-珀罗传感器的反射光谱整体平移,相应的频域信号只产生相移而形状不发生变化,因而不能采用普通光纤法布里-珀罗(FFP)传感器的腔长傅里叶变换解调法解调频分复用光纤光栅法布里-珀罗传感器的信号。根据这一特点,提出了利用自相关分析实现频分复用传感器系统信号解调的方案。 相似文献
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A novel and simple design technique for triangular spectrum response of fibre Bragg grating (FBG) is presented based on a linear chirped grating. It is shown that this method is fast and can give a straightforward solution to meet a design target. The numerical simulation examples verified the effectiveness of the design method. A general approach to design for multichannel triangular spectral responses for FBG filters is proposed, which provides a solution that achieves a minimum change of refractive index for the fibre. 相似文献