共查询到20条相似文献,搜索用时 15 毫秒
1.
Chan HB Marcet Z Woo K Tanner DB Carr DW Bower JE Cirelli RA Ferry E Klemens F Miner J Pai CS Taylor JA 《Optics letters》2006,31(4):516-518
We present measurements of transmission of infrared radiation through double-layer metallic grating structures. Each metal layer contains an array of subwavelength slits and supports transmission resonance in the absence of the other layer. The two metal layers are fabricated in close proximity to allow coupling of the evanescent field on individual layers. The transmission of the double layer is found to be surprisingly large at particular wavelengths, even when no direct line of sight exists through the structure as a result of the lateral shifts between the two layers. We perform numerical simulations using rigorous coupled wave analysis to explain the strong dependence of the peak transmission on the lateral shift between the metal layers. 相似文献
2.
Suxia Xie Hongjian Li Shaoli Fu Xin Zhou Haiqing Xu Jinjun Wu 《Solid State Communications》2010,150(27-28):1225-1230
We investigate numerically the transmittance of light through gold double-layer structures with periodic coaxial and non-coaxial slits. We attribute the enhanced optical transmission to the surface plasmon resonance collaborating with the localized waveguide resonance. The transmission spectra and the surface electric fields are used to characterize the resonances of both types. For the coaxial system, with the increase of the slit width of the second layer, the resonance peak values of both types increase sharply at first until the two layers have the same slit width and then decrease dramatically; additionally, the center of the localized waveguide resonance peak shifts to shorter wavelength noticeably, but the surface plasmon peak center moves negligibly. As regards the non-coaxial structure, it shows a similar behavior of the localized waveguide resonance peak to that of the coaxial one; however, the surface plasmon resonance peak behaves in a different way. These results may be associated with the surface plasmon coupling modes and the Fabry–Perot cavity modes in the double-layer structure. 相似文献
3.
We investigate the relationship between the transmission and the layer distance of double-layer gold slit arrays by using the finite-difference time-domain method.The results show that the transmission properties can be influenced strongly by layer distance.We attribute the two types of resonant modes to surface plasmon resonance and the localised waveguide resonance.We find that the localised waveguide transmission peak redshifts and becomes broader with increasing layer distance D.We also describe and explain the splitting,shift,and degeneration of the surface plasmon resonant transmission peak theoretically.In addition,to clarify the physical mechanism of the transmission behaviours,we analyse the distributions of electric field and total energy for the three transmission peaks with distance D=45 nm for the double-layer system.Light transporting behaviours are mostly concentrated in the region of the slits as well as the interspaces of the two layers,and for different resonant wavelengths the electric field and energy distributions are different.It is expected that the results obtained here will be helpful for designing subwavelength metallic grating devices. 相似文献
4.
Y. Pang 《Optics Communications》2007,280(1):10-15
Transmission of polarized light through subwavelength slit apertures is studied in visible and near infrared range wavelengths. We examine the roles played by the slit apertures, such as length, depth, period and number of slits. The experiment results, including dispersion curves, demonstrate among other things that the surface plasmon polariton and Fabry-Perot waveguide modes collectively dictate the transmission properties of subwavelength slit arrays and that as they approach each other, not only large gaps are formed but also mode interconversion occurs. These findings are discussed and compared to theoretical predictions. 相似文献
5.
We present the numerical investigation of the optical transmission through a periodic gold nano-slit structure composed with two non-identical layers, and compare it with that of double-layer structure with two identical layers. The optical enhancement is attributed to the surface Plasmon resonance collaborated with the localized waveguide resonance. It is shown that the transmission behaviors are strongly dependent on the layer separation and lateral displacement between the two single metallic gratings. Especially, it is found that extraordinary transmission exists even if the slit of one layer shifts laterally over that of the other one to the situation that no light can propagate directly when layer separation D = 0. When the slit widths of two layers are not equal, the surface plasmon resonance peak alternately decreases and increases twice, and the localized waveguide resonance peak appears at a longer wavelength as the lateral displacement varies for a non-zero layer separation, which differs from the situation with two identical layers. These transmission properties of the structures show promise for applications in optical devices. 相似文献
6.
7.
We report the observation of enhanced near-infrared transmission through arrays of subwavelength coaxial metallic structures compared with that through comparable diameter hole arrays as a result of localized electromagnetic modes supported by the complex coaxial unit cell. Polarization and angle-dependent transmission measurements clearly demonstrate the coupling between this localized mode and delocalized surface plasmon modes. A generalized, multiple discrete states Fano line shape provides a good fit to the experimental results. 相似文献
8.
Bin Hu Ben-Yuan Gu Bi-Zhen Dong Yan Zhang Ming Liu 《Central European Journal of Physics》2010,8(3):448-454
We compare the Fresnel-Kirchhoff diffraction formula, the superposition of cylindrical waves, and the twodimensional (2D)
Green’s function diffraction formula with a rigorous vector algorithm in calculating the near and intermediately transmitted
field of light through a one-dimensional metallic grating with subwavelength slits. It is found that the results calculated
by the 2D Green’s function diffraction formula coincide well with the precise result. The other evaluations deviate from the
exact result by varying proportions. Our findings may provide a useful and precise way to analyze the transmitted field features
of a metallic grating and subsequent possibility of achieving optimal designs for metallic optical elements with subwavelength
scale. 相似文献
9.
B.J. Lee 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(4):608-619
One-dimensional metallic slit array has been intensively studied in the spectral range from ultraviolet to near-infrared due to its enhanced transmission for transverse magnetic waves. However, the transmission enhancement is sensitive to the wavelength of incident radiation because of resonance characteristics. In this paper, we theoretically demonstrate that confining mid-infrared radiation to nanometer scales with a large transmission enhancement can be achieved from an aluminum slit array in a wavelength-insensitive manner, for potential applications in localized heating and nanothermal patterning. The Poynting vector and energy density calculated from the rigorous coupled-wave analysis (RCWA) are used to explain the strong localization of electromagnetic energy in the near-field regime. Furthermore, the localization of energy is also studied when a dielectric substrate is used to support the slit array in practical applications. 相似文献
10.
Suxia Xie Lisan Zeng Mengxiong Wu Zhijian Li Hongjian Li Bingju Zhou Lingxi Wu Renlong Zhou Jie Zhan 《Optik》2014
The transmission of a normally incident wave through a Z-shaped channel metallic slit array with metallic bar inside has been investigated by using finite-difference time-domain method. It is obtained that transmission spectra are nearly the same of the slit array with straight channel as that with Z-shaped channel in the condition the material of the slit array the same as that of the inner bar. If the Au bar is replaced by Al of the Au slit array, both resonance modes red shift obviously, especially for the structure with bent channel. Along with the width of the inner bar increasing, the localized waveguide resonance mode red shifts regularly with a tiny decrease of the peak value of all the kinds of composed structure introduced here, and the surface plasmon resonance mode red shifts regularly accompanied by peak value changing uniformly for the structures with only one type of metal. However, the surface plasmon resonance behaves different obviously, its center peak first moves to a larger wavelength fast, then red shifts slowly, for the Au-film Al-bar structure, but that moves in a very small wavelength range for the Al-film Au-bar one. The results obtained here are helpful to design subwavelength optical devices. 相似文献
11.
The mechanisms responsible for enhanced transmission of electromagnetic wave through an array of subwavelength slits in a metallic film are analyzed. Theoretical model of the enhanced transmission which takes into account the penetration of electromagnetic field into real metal is developed. Semi-analytical model based on Fabry–Perot formula is considered. Comparison of theoretical model, semi-analytical model and results of numerical simulation of Maxwell equations in time-dependent form (FDTD method) for silver with various geometric parameters is presented. The roles of surface plasmons and plasmon localized along slits are studied. 相似文献
12.
Analysis of phase shift of surface plasmon polaritons at metallic subwavelength hole arrays 下载免费PDF全文
We present the transmission spectra of light transmitting a metallic thin film perforated with differently shaped sub- wavelength hole arrays, which are calculated by a plane-wave-based transfer matrix method. We analyze the transmission peak positions and the phase-shift angles of different surface plasmon polariton (SPP) modes by using the microscopic theoretical model proposed by Haitao Liu and Philippe Lalanne [Liu Haitao, and Lalanne Philippe 2008 Nature 452 728], in which the phase shift properties of the SPPs scattered by the subwavelength hole arrays are considered. The results show that the transmission peak position and the minus phase shift angle of the SPP increase as the hole size increases. On the other hand, the effective dielectric constant of the metallic film can be deduced by the microscopic theoretical model. 相似文献
13.
Numerical investigation of the optical transmission through the one-dimensional subwavelength metallic cavity arrays (SMCA) is presented. Based on the finite-difference time-domain technique, we discuss the influence of the structural parameters on the transmission spectrum. The transmission peaks are attributed to the Fabry-Perot resonance; and the transmission dips are attributed to the surface plasmon resonance. For the SMCA with two cavities in one unit, the redshift of the transmission peak with increasing the distance between the two cavities originates from the depression of the coupling strength. These results obtained here will be helpful to design the plasmonic frequency-selecting device. 相似文献
14.
Superenhanced light transmission through subwavelength rectangular hole
arrays have been reported and some investigations have been made into the
physical origin of this phenomenon [K.J. Klein Koerkamp et al., Phys. Rev. Lett.
92, 183901 (2004)]. In our current work, by performing FDTD (finite
difference in the time domain) numerical simulations, we demonstrate that
mechanism that is different from surface plasmon polaritons set up by the
periodicity at the in-plane metal surfaces may account for this
superenhanced light transmission. We suggest that for arrays of rectangular
holes with small enough width in comparison to the wavelength of the
incident light, standing electromagnetic fields can be set up inside the
cavity by the surface plasmons on the hole walls with its intensity being
substantially enhanced inside the cavity. So resonant cavity-enhanced light
transmission is predominant and responsible for its superenhanced light
transmission. Rectangular holes behave as Fabry-Pérot resonance cavities
except that the frequency of their fundamental modes is restricted by their
TM cutoff frequency. However we believe that both localized surface plasmon
modes and surface plasmon polaritons set up by the periodicity at the
in-plane metal surfaces have their shares in extraordinary optical
transmission of rectangular hole arrays especially when the width of the
rectangular hole is not small enough and the metal film is not thick enough. 相似文献
15.
We investigate the effects of a bar on optical transmission through Z-shaped metallic slit arrays by using the finite-difference time domain (FDTD) method. A new hybrid Fabry-Perot (FP) surface plasmon polariton (SPP) mode emerges when changing the geometric parameters of the bar, and this mode can be viewed as a coupling between FP mode and SPP mode. In addition, an obvious dip appears in a featured area when the bar deviates from the central line, and a small displacement of the bar leads to tremendous change of the dip. These behaviors can be attributed to the phase resonance. In short, the structure is very sensitive to the metal bar. Furthermore, it combines photonic device miniaturization with sensitivity, which is useful for making optical switches. 相似文献
16.
17.
Bravo-Abad J Fernández-Domínguez AI García-Vidal FJ Martín-Moreno L 《Physical review letters》2007,99(20):203905
By using a theoretical formalism able to work in both real and k spaces, the physical origin of the phenomenon of extraordinary transmission of light through quasiperiodic arrays of holes is revealed. Long-range order present in a quasiperiodic array selects the wave vector(s) of the surface electromagnetic mode(s) that allows an efficient transmission of light through subwavelength holes. 相似文献
18.
《Physics letters. A》2005,344(6):451-456
By using FDTD numerical simulations, we show that mechanism that is different from surface plasmon polaritons set up by the periodicity at the in-plane metal surfaces may account for the superenhanced light transmission through coaxial hole arrays. We propose that resonant cavity-enhanced light transmission is responsible for it. When an axis is introduced into a hole, slits of definite length are formed. We suppose that a coaxial hole will support the standing waves of Fabry–Pérot-like modes with frequency higher than its cutoff frequency if its gap is small enough in comparison to the wavelength of the incident light and if the metal film is thick enough. 相似文献
19.
Y. Poujet M. Roussey J. Salvi F.I. Baida D. Van Labeke A. Perentes C. Santschi P. Hoffmann 《Photonics and Nanostructures》2006,4(1):47-53
This paper presents experimental studies of the enhanced light transmission through metallic films pierced by subwavelength annular apertures. Two different methods (e-beam lithography and focused ion beam) have been used to build the nano-structures. We have experimentally recorded their far-field spectral response in the visible range and the optical near-field above the nano-structures when they are excited at 633 nm. The spectral response exhibits a transmission peak at 700 nm with maximum efficiency around 16%. The near-field exhibits a characteristic two-lobe structure just above the aperture. Finite difference time domain (FDTD) simulations reproduce quite well the experimental results. 相似文献
20.
We propose a physical understanding of scattering by subwavelength grooves surrounding a single perfect conductor slit based
on the superposition of a cylindrical traveling surface wave and a standing surface wave. The collective reflection coefficient
was introduced to handle the multi-interaction of the surface wave between subwavelength grooves, and a slit–grooves focusing
structure was designed to demonstrate its validity. In comparison to numerical simulations by the finite difference time domain
method, the proposed method proves effective in describing the multi-interaction behavior of a surface wave and in further
refining the phase perturbation at the grooves’ exits. 相似文献